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	$ 75,759	$ 69,585	$ 143,889	$ 135,539
Other comprehensive income (loss)
Reclassification adjustments for derivatives, net of tax	1,093	1,126	2,190	2,256
Pension and other postretirement adjustments, net of tax	591	820	1,262	1,600
Cumulative translation adjustment	(27,043)	23,743	(10,826)	(32,894)
Other comprehensive income (loss)	(25,359)	25,689	(7,374)	(29,038)
Comprehensive income	$ 50,400	$ 95,274	$ 136,515	$ 106,501