Employee Benefit Plans - Schedule of Benefit Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Liability, Defined Benefit Plan, Noncurrent	$ 15,773	$ 16,240
Change in benefit obligation:
Benefit obligation, Beginning balance	40,722	40,296
Service Cost	0	0
Interest Cost	1,725	1,855
Actuarial losses	3,088	2,502
Benefit obligation, Ending balance	43,750	40,722
Change in plan assets:
Fair value of plan assets, Beginning balance	24,482	25,190
Actual return on plan assets	3,360	198
Employer contributions	1,920	3,025
Fair value of plan assets, Ending balance	27,977	24,482
Defined Benefit Plan, Benefit Obligation, Benefits Paid	1,785	3,931
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 1,785	$ 3,931