CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 83,844	$ 75,759	$ 159,743	$ 143,889
Other comprehensive income (loss)
Reclassification adjustments for derivatives, net of tax	1,063	1,093	2,105	2,190
Pension and other postretirement adjustments, net of tax	1,280	591	2,404	1,262
Cumulative translation adjustment	47,314	(27,043)	68,364	(10,826)
Other comprehensive income (loss)	49,657	(25,359)	72,873	(7,374)
Comprehensive income	$ 133,501	$ 50,400	$ 232,616	$ 136,515