Accumulated Other Comprehensive Loss (Components of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (579,196)	$ (569,430)
Other comprehensive income (loss) before reclassifications	(77,390)	6,738
Amounts reclassified from AOCL	2,400	1,486
Other comprehensive income (loss)	(74,990)	8,224
Ending balance	(654,186)	(561,206)
Accumulated other comprehensive loss, accumulated net loss from net investment hedge	8,500	12,200
Foreign currency translation items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(441,364)	(447,925)
Other comprehensive income (loss) before reclassifications	(81,353)	6,945
Amounts reclassified from AOCL	0	0
Other comprehensive income (loss)	(81,353)	6,945
Ending balance	(522,717)	(440,980)
Pension and other post-retirement effects
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(137,161)	(120,647)
Other comprehensive income (loss) before reclassifications	3,909	(269)
Amounts reclassified from AOCL	2,400	1,486
Other comprehensive income (loss)	6,309	1,217
Ending balance	(130,852)	(119,430)
Cash flow hedging activity
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(671)	(858)
Other comprehensive income (loss) before reclassifications	54	62
Amounts reclassified from AOCL	0	0
Other comprehensive income (loss)	54	62
Ending balance	(617)	(796)
Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss)	840	677
Accumulated other comprehensive income (loss), foreign currency translation adjustment, net of tax	$ 5,900	$ 5,200	$ 5,100	$ 4,500