Shareholders' Equity - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	$ (170,478)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(25,827)	$ 58,849	$ (28,720)
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(196,305)	(170,478)
Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(170,478)	(229,327)	(200,607)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(24,602)	56,568	(30,848)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(1,225)	2,281	2,128
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(25,827)	58,849	(28,720)
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(196,305)	(170,478)	(229,327)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(128,648)	(182,986)	(158,009)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(28,841)	53,854	(23,570)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	484	(1,407)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(28,841)	54,338	(24,977)
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(157,489)	(128,648)	(182,986)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	966	43	318
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	2,586	360	(1,087)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(2,351)	563	812
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	235	923	(275)
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	1,201	966	43
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(14,380)	(14,380)	(14,380)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	0
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(14,380)	(14,380)	(14,380)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(28,416)	(32,004)	(28,536)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	1,653	2,354	(6,191)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,126	1,234	2,723
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	2,779	3,588	(3,468)
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	$ (25,637)	$ (28,416)	$ (32,004)