Employee Benefit Plans - Components of Periodic Pension Costs and Other Amounts Recognized in Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Interest cost	$ 465	$ 403
Expected return on plan assets	(665)	(652)
Amortization of prior service benefit and net loss	220	174
Net periodic pension benefit	20	(75)
Amortization of prior service benefit and net loss	(220)	(174)
Net loss	671	657
Total recognized in other comprehensive loss	451	483
Total recognized in net periodic benefit and other comprehensive loss	$ 471	$ 408