Employee Benefit Plans - Summary of Projected Benefit Obligation in Excess of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 84,621	$ 92,384
Fair value of plan assets	45,713	59,096
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 52,274	$ 52,374