Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive (Loss) by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
AOCI Attributable to Parent [Roll Forward]
Beginning balance	$ 3,204,796
Other comprehensive loss before reclassifications	(295)	$ (201,913)
Amounts reclassified from accumulated other comprehensive loss	13,037	9,892
Other comprehensive income (loss), net of income taxes	12,742	(192,021)
Ending balance	3,324,563
Pension and Other Post-Retirement Benefits
AOCI Attributable to Parent [Roll Forward]
Beginning balance	(692,868)	(704,415)
Other comprehensive loss before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive loss	9,296	8,448
Other comprehensive income (loss), net of income taxes	9,296	8,448
Ending balance	(683,572)	(695,967)
Net Investment Hedge
AOCI Attributable to Parent [Roll Forward]
Beginning balance	(30,007)	(20,671)
Other comprehensive loss before reclassifications	0	(19,300)
Amounts reclassified from accumulated other comprehensive loss	3,741	1,444
Other comprehensive income (loss), net of income taxes	3,741	(17,856)
Ending balance	(26,266)	(38,527)
Foreign Currency Translation
AOCI Attributable to Parent [Roll Forward]
Beginning balance	(313,627)	(416,222)
Other comprehensive loss before reclassifications	(295)	(182,613)
Amounts reclassified from accumulated other comprehensive loss	0	0
Other comprehensive income (loss), net of income taxes	(295)	(182,613)
Ending balance	(313,922)	(598,835)
Total
AOCI Attributable to Parent [Roll Forward]
Beginning balance	(1,036,502)	(1,141,308)
Ending balance	$ (1,023,760)	$ (1,333,329)