Accumulated Other Comprehensive Loss (Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			$ 5,804,611
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings			(123,550)
Reclassifications to income			7,370
Other comprehensive (loss) income	$ 11,643	$ 31,954	(116,180)	$ 60,742
Balance at end of period	4,773,482	$ 5,098,545	4,773,482	$ 5,098,545
Reclassifications before taxes, included in net periodic benefit expense			769
Reclassifications, income tax expense			161
Foreign Currency Translation Gains (Losses)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(353,252)
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings			(67,843)
Reclassifications to income			0
Other comprehensive (loss) income			(67,843)
Balance at end of period	(421,095)		(421,095)
Retirement and Postretirement Benefit Plan Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(218,015)
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings			(55,707)
Reclassifications to income			6,762
Other comprehensive (loss) income			(48,945)
Balance at end of period	(266,960)		(266,960)
Reclassifications before taxes, included in net periodic benefit expense			8,987
Deferred Loss on Interest Rate Derivative Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(2,894)
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings			0
Reclassifications to income			608
Other comprehensive (loss) income			608
Balance at end of period	(2,286)		(2,286)
Reclassifications, income tax expense			2,225
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(574,161)
Components of other comprehensive income (loss):
Balance at end of period	$ (690,341)		$ (690,341)