CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 245,713	$ 188,751	$ 151,748
Foreign currency:
Foreign currency translation continuing operations adjustments, net of tax of $24,150, $24,818 and $(8,086), respectively	(110,671)	(105,410)	(9,637)
Foreign currency translation, net of tax	(110,671)	(105,410)	(9,637)
Pension and other postretirement benefits plans:
Prior service cost recognized in net periodic cost, net of tax of $9 and $9 in 2014 and 2013, respectively	0	(12)	(12)
Transition obligation recognized in net periodic cost, net of tax of $(2) in 2013	0	0	3
Unamortized (loss) gain arising during the period, net of tax of $1,469, $26,624 and $(14,638), respectively	(2,137)	(48,245)	25,641
Net loss recognized in net periodic cost, net of tax of $(2,242), $(1,544) and $(2,446), respectively	4,133	2,841	4,765
Foreign currency translation, net of tax of $(316), $(265) and $(66), respectively	861	709	(177)
Pension and other postretirement benefits plans adjustment, net of tax	2,857	(44,707)	30,220
Derivatives qualifying as hedges:
Unrealized gain (loss) on derivatives arising during the period, net of tax $379, $(111) and $(265), respectively	(2,974)	594	(549)
Reclassification adjustment on derivatives included in net income, net of tax of $(196), $111 and $46, respectively	483	(594)	930
Derivatives qualifying as hedges, net of tax	(2,491)	0	381
Other comprehensive (loss) income, net of tax	(110,305)	(150,117)	20,964
Comprehensive income	135,408	38,634	172,712
Less: comprehensive income attributable to noncontrolling interest	774	995	638
Comprehensive income attributable to common shareholders	$ 134,634	$ 37,639	$ 172,074