Other Comprehensive Income - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (302,592)	$ (345,605)	$ (334,925)	$ (323,673)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	5,934	(3,951)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	20,864	(27,275)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5,535	9,294
Other Comprehensive Income (Loss), Net of Tax	32,333	(21,932)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(19,384)	(82,341)	(31,101)	(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	11,717	(21,326)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax	11,717	(21,326)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(277)	(2,978)	(1,479)	(1,222)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	5,934	(3,951)
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	(4,732)	2,195
Other Comprehensive Income (Loss), Net of Tax	1,202	(1,756)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(282,931)	(260,286)	$ (302,345)	$ (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	9,147	(5,949)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	10,267	7,099
Other Comprehensive Income (Loss), Net of Tax	$ 19,414	$ 1,150