Employee Retirement Plans - Defined Contribution and Nonqualified Plans(Details) - USD ($) $ in Thousands  | 
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015  | 
Dec. 31, 2014  | 
Dec. 31, 2013  | 
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| Defined contribution plan | |||
| Company's matching contributions | $ 377 | $ 255 | $ 213 | 
| Non-discretionary employer contributions | 1,264 | 1,021 | $ 807 | 
| Non-qualified plan | |||
| Defined contribution plan | |||
| Expense | 496 | 509 | |
| Amount accrued | 2,482 | $ 1,708 | |
| Henderson Defined Contribution Plan [Member] | |||
| Defined contribution plan | |||
| Company's matching contributions | $ 299 | ||
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- Definition Represents amount of non-discretionary contributions made by an employer to a defined contribution plan. No definition available. 
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- Definition The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- References No definition available. 
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- Definition The amount of the cost recognized during the period for defined contribution plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition This represents the entire liability recognized in the balance sheet that is associated with the defined benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
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- Details 
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