Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (311,744)	$ (334,925)	$ (347,701)	$ (323,673)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	8,274	(1,704)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	17,222	(27,475)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(2,315)	5,151
Other Comprehensive Income (Loss), Net of Tax	23,181	(24,028)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(27,867)	(31,101)	(83,465)	(61,015)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	3,234	(22,450)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax	3,234	(22,450)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(672)	(1,479)	(1,278)	(1,222)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	8,274	(1,704)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(7,467)	1,648
Other Comprehensive Income (Loss), Net of Tax	807	(56)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(283,205)	(302,345)	$ (262,958)	$ (261,436)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	13,988	(5,025)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5,152	3,503
Other Comprehensive Income (Loss), Net of Tax	$ 19,140	$ (1,522)