CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 152,149	$ 137,664	$ 123,330
Other comprehensive earnings/(loss), net of tax
Pension and other postretirement benefit plans	9,070	(25,575)	28,102
Foreign currency translation adjustments	(14,760)	(8,142)	(2,906)
Other comprehensive earnings/(loss)	(5,690)	(33,717)	25,196
Comprehensive earnings	$ 146,459	$ 103,947	$ 148,526