Retirement Plans (Details) - Defined Benefit Plan [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 502	$ 654	$ 1,508	$ 1,977
Interest cost	414	467	1,259	1,412
Expected return on plan assets	(286)	(321)	(883)	(967)
Amortization of actuarial loss	54	72	162	219
Settlement expense	0	506	0	506
Total defined benefit expense	$ 684	$ 1,378	$ 2,046	$ 3,147