Employee Benefit Plans - Components of Net Periodic Benefit Cost (Details) - Supplemental Executive Retirement Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 330	$ 291	$ 660	$ 582
Interest cost	96	73	192	147
Net periodic benefit cost	$ 426	$ 364	$ 852	$ 729