Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018	Jan. 01, 2017
Accumulated Other Comprehensive Income (Loss)
Balance	$ 101,842	$ 30,553	$ (103,660)
Other comprehensive income (loss) before reclassifications	81,471	(101,811)	116,679
Amounts reclassified from accumulated other comprehensive income (loss)	27,347	64,023	28,514
Other comprehensive income (loss), net of tax	108,818	(37,788)	145,193
Cumulative effect of accounting changes				$ (12,207)	$ (137,429)
Balance	286,096	101,842	30,553
Cash flow hedges
Accumulated Other Comprehensive Income (Loss)
Balance	191	(406)	(1,485)
Other comprehensive income (loss) before reclassifications	278	(763)	(288)
Amounts reclassified from accumulated other comprehensive income (loss)	(132)	1,447	1,367
Other comprehensive income (loss), net of tax	146	684	1,079
Cumulative effect of accounting changes			(87)
Restated balance at December 31, 2017			(493)
Balance	337	191	(406)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Balance	(3,061)	1,597	120
Other comprehensive income (loss) before reclassifications	6,719	(2,579)	1,158
Amounts reclassified from accumulated other comprehensive income (loss)	(809)	(2,423)	319
Other comprehensive income (loss), net of tax	5,910	(5,002)	1,477
Cumulative effect of accounting changes			344
Restated balance at December 31, 2017			1,941
Balance	2,849	(3,061)	1,597
Pension and postretirement benefit plans
Accumulated Other Comprehensive Income (Loss)
Balance	(846,461)	(748,800)	(787,813)
Other comprehensive income (loss) before reclassifications	(845)	(46,170)	12,185
Amounts reclassified from accumulated other comprehensive income (loss)	28,288	64,999	26,828
Other comprehensive income (loss), net of tax	27,443	18,829	39,013
Cumulative effect of accounting changes			(116,490)
Restated balance at December 31, 2017			(865,290)
Balance	(819,018)	(846,461)	(748,800)
Foreign currency adjustments
Accumulated Other Comprehensive Income (Loss)
Balance	(99,630)	(47,331)	(150,955)
Other comprehensive income (loss) before reclassifications	75,319	(52,299)	103,624
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Other comprehensive income (loss), net of tax	75,319	(52,299)	103,624
Cumulative effect of accounting changes			0
Restated balance at December 31, 2017			(47,331)
Balance	(24,311)	(99,630)	(47,331)
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss)
Balance	(948,961)	(794,940)	(940,133)
Cumulative effect of accounting changes			(116,233)	$ (116,233)
Restated balance at December 31, 2017			(911,173)
Balance	$ (840,143)	$ (948,961)	$ (794,940)