Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 47,911	$ 51,155	$ 88,078	$ 79,506
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	3,335	6,224	5,403	(13,883)
Interest rate hedges – net change in deferred loss	(1,946)	434	(9,079)	(670)
Pension – net change in deferred actuarial loss	38	53	75	106
Other comprehensive income (loss), net of tax	1,427	6,711	(3,601)	(14,447)
Comprehensive income	$ 49,338	$ 57,866	$ 84,477	$ 65,059