Employee Benefit Plans - Postretirement Healthcare Plan (Details) - Postretirement Healthcare Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure
Minimum age requirement	55 years
Requisite service period	15 years
Unfunded benefit obligation	$ 3,921	$ 3,577
Net periodic benefit cost	$ 400	$ 400	$ 571
Assumptions used calculating net periodic benefit cost, discount rate	3.60%	3.60%
Assumptions used calculating net periodic benefit cost, rate of compensation increase	6.00%	6.50%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2015	$ 163
2016	194
2017	219
2018	254
2019	295
2020 through 2024	1,500
Accumulated other comprehensive income (loss), before tax, related to the Plan	555
Accumulated other comprehensive income (loss), net of tax	378
Net acturarial loss, net of tax	255
Unamortized transition asset, net of tax	300
Estimated amount amortized from accumulated other comprehensive loss into net periodic benefit costs	$ 35