Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss)	$ (190,500)	$ (106,399)
Other comprehensive income before reclassifications to consolidated statements of income	(27,868)	(75,597)
Amounts reclassified from accumulated other comprehensive (loss) income to the consolidated statements of income	7,873	10,827
Total other comprehensive (loss) income, net of tax	(19,995)	(64,770)	$ 94,429
Amounts reclassified from accumulated other comprehensive income to retained earnings		0
Accumulated other comprehensive income (loss)	(210,495)	(190,500)	(106,399)
Gains and Losses on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss)	834	72
Other comprehensive income before reclassifications to consolidated statements of income	(1,436)	(410)
Amounts reclassified from accumulated other comprehensive (loss) income to the consolidated statements of income	487	1,083
Total other comprehensive (loss) income, net of tax	(949)	673
Amounts reclassified from accumulated other comprehensive income to retained earnings		89
Accumulated other comprehensive income (loss)	(115)	834	72
Pension and Other Postretirement Benefit Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss)	(138,690)	(103,844)
Other comprehensive income before reclassifications to consolidated statements of income	(12,743)	(25,170)
Amounts reclassified from accumulated other comprehensive (loss) income to the consolidated statements of income	7,386	9,744
Total other comprehensive (loss) income, net of tax	(5,357)	(15,426)
Amounts reclassified from accumulated other comprehensive income to retained earnings		(19,420)
Accumulated other comprehensive income (loss)	(144,047)	(138,690)	(103,844)
Foreign Currency Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss)	(52,644)	(2,627)
Other comprehensive income before reclassifications to consolidated statements of income	(13,689)	(50,017)
Amounts reclassified from accumulated other comprehensive (loss) income to the consolidated statements of income	0	0
Total other comprehensive (loss) income, net of tax	(13,689)	(50,017)
Amounts reclassified from accumulated other comprehensive income to retained earnings		0
Accumulated other comprehensive income (loss)	$ (66,333)	(52,644)	$ (2,627)
Accumulated Other Non-Owner Changes to Equity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated other comprehensive income to retained earnings		$ (19,331)