Retirement Plans (Details) - Defined Benefit Plan [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 654	$ 610	$ 1,977	$ 1,877
Interest cost	467	502	1,412	1,704
Expected return on plan assets	(321)	(478)	(967)	(1,432)
Amortization of prior service cost	0	43	0	129
Amortization of actuarial loss (gain)	72	(14)	219	(331)
Settlement expense	506	289	506	289
Curtailment gain	0	0	0	(115)
Total defined benefit expense	$ 1,378	$ 952	$ 3,147	$ 2,121