Employee Benefit Plans (Details 2) - Supplemental Executive Retirement Plan (SERP) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Weighted-average assumptions used to measure SERP obligation:
Discount Rate (as a percent)	3.82%	3.64%
Salary Increases (as a percent)	4.00%	5.00%
Components of net periodic pension cost
Service cost	$ 3,518	$ 5,517	$ 5,406
Interest cost	1,836	2,367	1,584
Amortization of prior service cost	1,234	1,234	827
Amortization of net actuarial loss	160	210	794
Total	$ 6,748	$ 9,328	$ 8,611