Retirement Plans (Details) - Defined Benefit Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 503	$ 662
Interest cost	420	472
Expected return on plan assets	(297)	(322)
Amortization of actuarial loss	53	73
Total defined benefit expense	$ 679	$ 885