| **Stock-Based Compensation - Summary of Restricted Stock, Stock Grants, Stock Units and Performance Shares (Details) - $ / shares** | 12 Months Ended |
|-------------------------------------------------------------------------------------------------------------------------------------|-----------------|
||
| Restricted Stock Units, Stock Grants, and Stock Units                                                                               |            |   |   |
| **Stocks granted and the weighted average fair value**                                                                              |            |   |   |
| Units granted (in shares)                                                                                                           | 161,963         | 141,811 | 152,651 |
| Grant date fair value (in dollars per share)                                                                                        | $ 72.60         | $ 67.34 | $ 64.12 |
| Number of granted awards to be settled in cash (in shares)                                                                          | 67,599          | 43,952 | 45,104 |
| Performance Shares                                                                                                                  |            |   |   |
| **Stocks granted and the weighted average fair value**                                                                              |            |   |   |
| Units granted (in shares)                                                                                                           | 147,706         | 166,666 | 151,430 |
| Grant date fair value (in dollars per share)                                                                                        | $ 78.99         | $ 66.60 | $ 64.97 |

| X                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of units granted during the period on other than stock (or unit) option plans.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Number of Awards to be Settled in Cash
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901
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| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------|
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