Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Leases [Abstract]
Rental expense for all non-cancelable operating leases	$ 17,600	$ 17,500	$ 19,600
Future minimum rentals under operating leases:
Future minimum operating lease payments due, 2017	14,491
Future minimum operating lease payments due, 2018	13,525
Future minimum operating lease payments due, 2019	12,302
Future minimum operating lease payments due, 2020	11,295
Future minimum operating lease payments due, 2021	8,721
Future minimum operating lease payments due, 2022 and thereafter	$ 35,991