Stockholders' Equity Stockholders' Equity (Performance Awards) (Details) - USD ($)
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3 Months Ended |
Feb. 23, 2016 |
Mar. 31, 2016 |
Mar. 31, 2015 |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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| Share-Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions, Simulation Period |
4 years 10 months 10 days
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| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value |
$ 20.06
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|
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| Share-Based Compensation Arrangement, By Share-Based Payment Award, Equity Instrument Other Than Options, Percent Represented By EBITDA |
|
25.00%
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| Share-Based Compensation Aggrangement, By Share-Based Payment Award, Equity Instrument Other Than Options, Percent Represented By Relative Shareholder Return Performance |
|
75.00%
|
|
| Directors compensation expense |
|
$ 124,000
|
$ 92,000
|
| Share-Based Compensation Arrangement By Share-Based Payment Award, Fair Value Assumptions, Forfeiture Rate |
2.00%
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|
| Performance Shares [Member] |
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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|
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| Expected volatility assumption (in Percent) |
31.20%
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|
|
| Risk-free interest rate assumption (in Percent) |
1.21%
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|
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| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |
|
73,700
|
|
| Officers And Key Employees [Member] |
|
|
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
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| Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Granted In Period, Fair Value |
|
$ 1,605,186
|
|
| Directors compensation expense |
|
$ 27,000
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