Equity and Share-Based Compensation - Additional Information (Detail) - USD ($) |
3 Months Ended | |
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Mar. 31, 2018 |
Mar. 31, 2017 |
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Stock compensation expense | $ 254,000 | $ 413,000 |
| Options exercised during period | 29,800 | |
| Proceeds from stock options exercised | $ 200,000 | |
| 2009 Long-Term Incentive Plan [Member] | Class A Common Stock [Member] | Independent Directors Compensation Plan [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Issuance of shares for compensation | 452 | |
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement. 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 Number of shares issued in lieu of cash for services contributed to the entity. Number of shares includes, but is not limited to, shares issued for services contributed by vendors and founders. No definition available.
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- Definition Number of share options (or share units) exercised during the current period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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