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Employee Savings Plan - Additional Information (Detail) - USD ($) | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract] |  |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Match | 50.00% |  |
Minimum age to be eligible to defined contribution plan | 21 years |  |
Maximum contribution by company expressed as percentage of employee pre-tax salary | 25.00% |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay | 6.00% |  |
Company contributions vest at end of two years | 20.00% |  |
Company contributions vest at end of three years | 40.00% |  |
Company contributions vest at end of four years | 60.00% |  |
Company contributions vest at end of five years | 100.00% |  |
Company contributions to employee savings plan | $ 1,712,000 | $ 1,845,000 | $ 1,555,000

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- Definition Company contributions vest at end of five years. + References No definition available. + Details
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- Definition Company contributions vest at end of four years. + References No definition available. + Details
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- Definition Company contributions vest at end of three years. + References No definition available. + Details
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- Definition Company contributions vest at end of two year. + References No definition available. + Details
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- Definition Minimum age to be eligible to defined contribution plan. + References No definition available. + Details
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- Definition The amount of the cost recognized during the period for defined contribution plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
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- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
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