Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
Jan. 01, 2018	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 5,950,628	$ 4,427,749		$ 4,654,574	$ 4,774,595		$ 5,950,628	$ 4,654,574	$ 5,950,628
Stranded tax effect resulting from the Tax Cuts and Jobs Act	(5,540)
Other comprehensive income (loss) before reclassifications		(1,054)	$ (406)	508	(483)	$ (2,771)	667
Amounts reclassified from AOCI		549	549	550	324	325	324
Other comprehensive income (loss), net		(505)	143	1,058	(159)	(2,446)	991	696	(1,614)
Ending Balance		3,715,214	4,427,749		4,691,667	4,774,595		3,715,214	4,691,667
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(27,603)	(37,959)	(38,508)	(39,058)	(32,494)	(32,819)	(27,603)	(39,058)	(27,603)
Stranded tax effect resulting from the Tax Cuts and Jobs Act	(5,540)
Other comprehensive income (loss) before reclassifications		0	0	0	0	0	0
Amounts reclassified from AOCI		549	549	550	324	325	324
Other comprehensive income (loss), net		549	549	550	324	325	324
Ending Balance	(33,143)	(37,410)	(37,959)	(38,508)	(32,170)	(32,494)	(32,819)	(37,410)	(32,170)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(15,285)	(17,912)	(17,506)	(18,014)	(17,389)	(14,618)	(15,285)	(18,014)	(15,285)
Stranded tax effect resulting from the Tax Cuts and Jobs Act	0
Other comprehensive income (loss) before reclassifications		(1,054)	(406)	508	(483)	(2,771)	667
Amounts reclassified from AOCI		0	0	0	0	0	0
Other comprehensive income (loss), net		(1,054)	(406)	508	(483)	(2,771)	667
Ending Balance	(15,285)	(18,966)	(17,912)	(17,506)	(17,872)	(17,389)	(14,618)	(18,966)	(17,872)
Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(42,888)	(55,871)	(56,014)	(57,072)	(49,883)	(47,437)	(42,888)	(57,072)	(42,888)
Other comprehensive income (loss), net		(505)			(159)			696	(1,614)
Ending Balance	$ (48,428)	$ (56,376)	$ (55,871)	$ (56,014)	$ (50,042)	$ (49,883)	$ (47,437)	$ (56,376)	$ (50,042)

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act.

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