Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 55,077	$ 103,406	$ 130,174	$ 124,201
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	23,817	12,761	(22,564)	5,525
Interest rate swaps – net change in deferred gain or loss	2,900	(24,715)	(41,832)	(39,220)
Pension plans – net change in deferred actuarial loss	80	41	159	83
Other comprehensive loss, net of tax	26,797	(11,913)	(64,237)	(33,612)
Comprehensive income	$ 81,874	$ 91,493	$ 65,937	$ 90,589