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]
Reclassified actuarial net losses	$ (2,100)	$ (1,900)	$ (1,600)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax	1,000
Retirement Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), December 31, 2017	(12,066)	(11,209)	(10,482)
Other comprehensive income (loss) before reclassifications	3,207	(2,796)	(2,716)
Income tax	(834)	727	869
Other comprehensive income (loss) before reclassifications, net of tax	2,373	(2,069)	(1,847)
Amounts reclassified from accumulated other comprehensive income (loss)	2,090	1,933	1,646
Income tax	(543)	(721)	(526)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1,547	1,212	1,120
Other comprehensive income (loss)	3,920	(857)	(727)
Accumulated other comprehensive income (loss), December 31, 2018	(8,146)	(12,066)	(11,209)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), December 31, 2017	(13,185)	(56,245)	(41,228)
Other comprehensive income (loss) before reclassifications	(19,366)	43,060	(15,017)
Income tax	0	0	0
Other comprehensive income (loss) before reclassifications, net of tax	(19,366)	43,060	(15,017)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Income tax	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	0	0
Other comprehensive income (loss)	(19,366)	43,060	(15,017)
Accumulated other comprehensive income (loss), December 31, 2018	(32,551)	(13,185)	(56,245)
Derivatives and Other
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), December 31, 2017	167	(29)	(115)
Other comprehensive income (loss) before reclassifications	(7,867)	196	86
Income tax	2,099	0	0
Other comprehensive income (loss) before reclassifications, net of tax	(5,768)	196	86
Amounts reclassified from accumulated other comprehensive income (loss)	954	0	0
Income tax	(268)	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	686	0	0
Other comprehensive income (loss)	(5,082)	196	86
Accumulated other comprehensive income (loss), December 31, 2018	(4,915)	167	(29)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), December 31, 2017	(25,084)	(67,483)	(51,825)
Other comprehensive income (loss) before reclassifications	(24,026)	40,460	(17,647)
Income tax	1,265	727	869
Other comprehensive income (loss) before reclassifications, net of tax	(22,761)	41,187	(16,778)
Amounts reclassified from accumulated other comprehensive income (loss)	3,044	1,933	1,646
Income tax	(811)	(721)	(526)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	2,233	1,212	1,120
Other comprehensive income (loss)	(20,528)	42,399	(15,658)
Accumulated other comprehensive income (loss), December 31, 2018	$ (45,612)	$ (25,084)	$ (67,483)