Employee Benefit Plans (Details 4) - Supplemental Executive Retirement Plan (SERP) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amounts relating to the SERP that have been recognized in other comprehensive gain (loss)
Net unrecognized actuarial gain	$ 1,539	$ 5,035	$ 3,956
Net unrecognized prior service cost (benefit)	1,234	(2,627)	827
Total	2,773	2,408	4,783
Tax benefit	(1,070)	(920)	(1,688)
Total, net of tax	1,703	1,488	3,095
Accumulated other comprehensive income (loss) that have not yet been recognized as a component of net periodic pension cost
Net unrecognized actuarial loss	1,228	2,767	7,803
Net unrecognized prior service cost	7,093	8,326	5,698
Total	8,321	11,093	13,501
Tax benefit	(3,067)	(4,150)	(5,074)
Total, net of tax	5,254	$ 6,943	$ 8,427
Amounts included in accumulated other comprehensive income expected to be recognized as components of net periodic pension expense
Amortization of prior service cost	1,234
Total	$ 1,234