| **Stock-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands**          | 9 Months Ended |
|-----------------------------------------------------------------------------------------------------------|----------------|
||
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Granted                                                                                                   | 225,712        |   |
| Share Based Compensation                                                                                  | $ 3,642        | $ 4,728 |
| 2004 Plan [Member]                                                                                        |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Number of shares authorized for issuance                                                                  | 0              |   |
| 2009 Plan [Member]                                                                                        |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Number of shares authorized for issuance                                                                  | 6,250,000      |   |
| Maximum number of shares may be issued pursuant to stock awards, stock units and other stock-based awards | 3,125,000      |   |
| Maximum number of shares subject to grants to any one individual in any one year                          | 500,000        |   |
| Underlying stock option and restricted stock awards available for grant                                   | 3,982,401      |   |
| Performance Share Units [Member]                                                                          |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Vesting period, in years                                                                                  | 3 years        |   |
| Weighted average fair value of stock awards granted                                                       | $ 28.89        | $ 26.45 |
| Amortization period of fair value of shares, in months                                                    | 36 months      |   |
| Granted                                                                                                   | 152,533        |   |
| Performance Share Units [Member] | Minimum [Member]                                                       |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Percentage of target award amount the grantee may earn                                                    | 0.00%          |   |
| Performance Share Units [Member] | Maximum [Member]                                                       |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Percentage of target award amount the grantee may earn                                                    | 200.00%        |   |
| Restricted Stock Units [Member]                                                                           |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Restricted period                                                                                         | 3 years        |   |
| Weighted average fair value of stock awards granted                                                       | $ 32.09        | $ 25.97 |
| Granted                                                                                                   | 50,324         |   |
| Stock Options [Member]                                                                                    |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Granted                                                                                                   | 0              | 0 |
| Stock Compensation Plan [Member]                                                                          |           |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                        |           |   |
| Weighted average fair value of stock awards granted                                                       | $ 32.570       | $ 26.44 |
| Granted                                                                                                   | 11,509         |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of grants made 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
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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
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The highest quantity of shares an employee can purchase under the plan per period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum Number Of Shares May Be Issued Pursuant To Stock Awards, Stock Units And Other Stock-Based Awards
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Percentage of target award amount the participant may earn
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| X                                                                                                                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Restricted Stock Units Restricted Period
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| X                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share based compensation arrangement by share based payment award amortization period of fair value of shares
+ References
No definition available.
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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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