Condensed Consolidated Statements of Comprehensive Income (Unaudited) Statement - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other comprehensive (loss)/income
Adoption of new accounting standards	$ 0	$ 0	$ 408	$ 0
Market value adjustments on interest rate swaps, net of tax	2,532	41	10,770	1,621
Foreign currency translation adjustments	(6,129)	6,078	(23,729)	22,761
Supplemental benefit plans adjustments, net of tax	(124)	(106)	(371)	1,519
Total other comprehensive (loss)/income	(3,721)	6,013	(12,922)	25,901
Net income	22,451	30,754	109,254	87,453
Comprehensive income	$ 18,730	$ 36,767	$ 96,332	$ 113,354