| **Consolidated Statements Of Capitalization (Parenthetical) (USD $)** | 12 Months Ended                                                                                                                                                                         |
|-----------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| Common stock, par value                                               | 0.50us-gaap_CommonStockParOrStatedValuePerShare                                                                                                                                         | 0.50us-gaap_CommonStockParOrStatedValuePerShare |
| Long Term Debt of Subsidiaries 0.00% to .99% [Member]                 |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesOneMember                                            | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesOneMember |
| Interest rate range, maximum                                          | 0.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesOneMember                                            | 0.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesOneMember |
| Maturity date range, start                                            | 2023                                                                                                                                                                                    | 2023 |
| Maturity date range, end                                              | 2033                                                                                                                                                                                    | 2033 |
| Long Term Debt of Subsidiaries 1.00% to 1.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 1.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTwoMember                                            | 1.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTwoMember |
| Interest rate range, maximum                                          | 1.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTwoMember                                            | 1.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTwoMember |
| Maturity date range, start                                            | 2016                                                                                                                                                                                    | 2016 |
| Maturity date range, end                                              | 2035                                                                                                                                                                                    | 2035 |
| Long Term Debt of Subsidiaries 2.00% to 2.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 2.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesThreeMember                                          | 2.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesThreeMember |
| Interest rate range, maximum                                          | 2.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesThreeMember                                          | 2.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesThreeMember |
| Maturity date range, start                                            | 2024                                                                                                                                                                                    | 2024 |
| Maturity date range, end                                              | 2031                                                                                                                                                                                    | 2031 |
| Long Term Debt of Subsidiaries 3.00% to 3.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 3.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFourMember                                           | 3.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFourMember |
| Interest rate range, maximum                                          | 3.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFourMember                                           | 3.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFourMember |
| Maturity date range, start                                            | 2016                                                                                                                                                                                    | 2016 |
| Maturity date range, end                                              | 2047                                                                                                                                                                                    | 2047 |
| Long Term Debt of Subsidiaries 4.00% to 4.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 4.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFiveMember                                           | 4.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFiveMember |
| Interest rate range, maximum                                          | 4.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFiveMember                                           | 4.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesFiveMember |
| Maturity date range, start                                            | 2020                                                                                                                                                                                    | 2020 |
| Maturity date range, end                                              | 2054                                                                                                                                                                                    | 2054 |
| Long Term Debt of Subsidiaries 5.00% to 5.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSixMember                                            | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSixMember |
| Interest rate range, maximum                                          | 5.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSixMember                                            | 5.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSixMember |
| Maturity date range, start                                            | 2015                                                                                                                                                                                    | 2015 |
| Maturity date range, end                                              | 2043                                                                                                                                                                                    | 2043 |
| Long Term Debt of Subsidiaries 6.00% to 6.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 6.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSevenMember                                          | 6.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSevenMember |
| Interest rate range, maximum                                          | 6.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSevenMember                                          | 6.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesSevenMember |
| Maturity date range, start                                            | 2015                                                                                                                                                                                    | 2015 |
| Maturity date range, end                                              | 2036                                                                                                                                                                                    | 2036 |
| Long Term Debt of Subsidiaries 7.00% to 7.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesEightMember                                          | 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesEightMember |
| Interest rate range, maximum                                          | 7.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesEightMember                                          | 7.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesEightMember |
| Maturity date range, start                                            | 2022                                                                                                                                                                                    | 2022 |
| Maturity date range, end                                              | 2027                                                                                                                                                                                    | 2027 |
| Long Term Debt of Subsidiaries 8.00% to 8.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 8.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesNineMember                                           | 8.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesNineMember |
| Interest rate range, maximum                                          | 8.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesNineMember                                           | 8.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesNineMember |
| Maturity date range, start                                            | 2021                                                                                                                                                                                    | 2021 |
| Maturity date range, end                                              | 2025                                                                                                                                                                                    | 2025 |
| Long Term Debt of Subsidiaries 9.00% to 9.99% [Member]                |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 9.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTenMember                                            | 9.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTenMember |
| Interest rate range, maximum                                          | 9.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTenMember                                            | 9.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesTenMember |
| Maturity date range, start                                            | 2018                                                                                                                                                                                    | 2018 |
| Maturity date range, end                                              | 2026                                                                                                                                                                                    | 2026 |
| Long-Term Debt Of Subsidiaries 10.00% To 10.99% [Member]              |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 10.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesElevenMember                                        | 10.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesElevenMember |
| Interest rate range, maximum                                          | 10.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesElevenMember                                        | 10.99%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_LongTermDebtOfSubsidiariesElevenMember |
| Maturity date                                                         | 2018                                                                                                                                                                                    | 2018 |
| Bank at 1.921% Percent [Member]                                       |                                                                                                                                                                                    |   |
| Interest rate                                                         | 1.921%us-gaap_DebtInstrumentInterestRateStatedPercentage/ us-gaap_DebtInstrumentAxis= wtr_BankAtOnePointNineTwoOnePercentMember                                                         | 1.921%us-gaap_DebtInstrumentInterestRateStatedPercentage/ us-gaap_DebtInstrumentAxis= wtr_BankAtOnePointNineTwoOnePercentMember |
| Maturity date                                                         | 2017                                                                                                                                                                                    | 2017 |
| Notes at 3.57% due 2027 [Member]                                      |                                                                                                                                                                                    |   |
| Interest rate                                                         | 3.57%us-gaap_DebtInstrumentInterestRateStatedPercentage/ us-gaap_DebtInstrumentAxis= wtr_NotesAtThreePointFiveSevenPercentMember                                                        | 3.57%us-gaap_DebtInstrumentInterestRateStatedPercentage/ us-gaap_DebtInstrumentAxis= wtr_NotesAtThreePointFiveSevenPercentMember |
| Maturity date                                                         | 2027                                                                                                                                                                                    | 2027 |
| Notes Ranging From 4.62% To 4.87% [Member]                            |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 4.62%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFourPointSixTwoPercentageToFourPointEightSevenPercentageMember | 4.62%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFourPointSixTwoPercentageToFourPointEightSevenPercentageMember |
| Interest rate range, maximum                                          | 4.87%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFourPointSixTwoPercentageToFourPointEightSevenPercentageMember | 4.87%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFourPointSixTwoPercentageToFourPointEightSevenPercentageMember |
| Maturity date range, start                                            | 2016                                                                                                                                                                                    | 2016 |
| Maturity date range, end                                              | 2024                                                                                                                                                                                    | 2024 |
| Notes Ranging From 5.01% To 5.95% [Member]                            |                                                                                                                                                                                    |   |
| Interest rate range, minimum                                          | 5.01%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFivePointZeroOnePercentageToFivePointNineFivePercentageMember  | 5.01%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFivePointZeroOnePercentageToFivePointNineFivePercentageMember |
| Interest rate range, maximum                                          | 5.95%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFivePointZeroOnePercentageToFivePointNineFivePercentageMember  | 5.95%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum/ us-gaap_DebtInstrumentAxis= wtr_NotesRangingFromFivePointZeroOnePercentageToFivePointNineFivePercentageMember |
| Maturity date range, start                                            | 2014                                                                                                                                                                                    | 2014 |
| Maturity date range, end                                              | 2037                                                                                                                                                                                    | 2037 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Face amount or stated value per share of common stock.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5
+ Details**Name:**us-gaap_CommonStockParOrStatedValuePerShare**Namespace Prefix:**us-gaap_**Data Type:**num:perShareItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
+ Details**Name:**us-gaap_DebtInstrumentInterestRateStatedPercentage**Namespace Prefix:**us-gaap_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum contractual interest rate for funds borrowed, under the debt agreement.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Minimum contractual interest rate for funds borrowed, under the debt agreement.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
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| X                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Debt Instrument Maturity Date End
+ References
No definition available.
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| X                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Debt Instrument Maturity Date Start
+ References
No definition available.
+ Details**Name:**wtr_DebtInstrumentMaturityDateStart**Namespace Prefix:**wtr_**Data Type:**xbrli:gYearItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Debt Instrument, Maturity Date, Year
+ References
No definition available.
+ Details**Name:**wtr_DebtInstrumentMaturityDateYear**Namespace Prefix:**wtr_**Data Type:**xbrli:gYearItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                          |
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| X                                                                                                                                                                                                    |
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| X                                                                                                                                                                                                     |
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