Share-Based Awards and Cash-Based Awards - Summary of Compensation Expense under Share-Based Payment Arrangements and Related Tax Benefit (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
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Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Share-based compensation | $ 8,065 | $ 11,013 | $ 10,242 |
| Tax benefit computed at the statutory rate | 1,694 | 3,855 | 3,585 |
| Restricted Stock Units (RSUs) | |||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Share-based compensation | 7,785 | 10,640 | 9,978 |
| Restricted Shares | |||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Share-based compensation | $ 280 | $ 373 | 358 |
| Common Stock | |||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Share-based compensation | $ (94) | ||
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- Definition The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- 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. No definition available.
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- Definition Share-based compensation paid in shares and cash. No definition available.
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