Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax	$ 8,481	$ (5,123)	$ 7,311	$ (8,073)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(51,691)		(51,691)			$ (51,247)
Other Comprehensive Income (Loss), Foreign Currency Translation, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	0	7,117	0	15,935
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	37	0	180	1
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(33,148)	(26,668)	(33,148)	(26,668)	$ (60,435)	(45,816)	$ (32,846)	$ (51,014)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	27,287	(15,863)	23,552	(25,000)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		22,041	(10,884)	49,346
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	0	0	0
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(4,945)	(2,782)	(4,945)	(2,782)	(5,045)	(5,431)	(2,784)	(2,787)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	0	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	100	2	486	5
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(38,093)	(29,450)	(38,093)	(29,450)	(65,480)	(51,247)	$ (35,630)	$ (53,801)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	27,287	(15,863)	23,552	(25,000)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		22,041	(10,884)	49,346
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	100	$ 2	486	$ 5
Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	13,598		13,598		5,580	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	7,969		13,581
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	49		17
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(51,691)		(51,691)		$ (71,060)	$ (51,247)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	19,318		9,971
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(10,884)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	$ 51		$ 469