Lease Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Leases [Abstract]
Rental expense under operating leases	$ 11,147	$ 11,375	$ 10,581
Future minimum lease payments for non-cancelable operating leases
Operating Leases, Future Minimum Payments Due, Next Twelve Months	9,400
Operating Leases, Future Minimum Payments, Due in Two Years	8,500
Operating Leases, Future Minimum Payments, Due in Three Years	7,000
Operating Leases, Future Minimum Payments, Due in Four Years	5,100
Operating Leases, Future Minimum Payments, Due in Five Years	3,100
Operating Leases, Future Minimum Payments, Due Thereafter	8,200
Operating Leases, Future Minimum Payments Due	$ 41,300