Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		$ 881,589
Other comprehensive income (loss) before reclassifications		11,188	$ 2,912	$ (14,878)
Amounts reclassified from OCI		(7,271)	(365)	46
Ending balance		934,336	881,589
Cumulative Effect, Period of Adoption, Adjustment [Member] | Adoption of ASU 2018-02 [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(1,389)
Ending balance				(1,389)
Accumulated Other Comprehensive (Loss) Income [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(163,008)	(165,555)	(149,334)
Ending balance		(159,091)	(163,008)	(165,555)
Cash Flow Hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]	(199)	147	(669)
Other comprehensive income (loss) before reclassifications	[1]	(374)	(111)	667
Amounts reclassified from OCI	[1]	1,322	(235)	149
Ending balance	[1]	749	(199)	147
Cash Flow Hedges [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Adoption of ASU 2018-02 [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]		0
Ending balance	[1]			0
Pension Items [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]	(672)	549	(309)
Other comprehensive income (loss) before reclassifications	[1]	(1,325)	(1,091)	1,130
Amounts reclassified from OCI	[1]	32	(130)	(103)
Ending balance	[1]	(1,965)	(672)	549
Pension Items [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Adoption of ASU 2018-02 [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]		(169)
Ending balance	[1]			(169)
Foreign Currency Items [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(162,137)	(166,251)	(148,356)
Other comprehensive income (loss) before reclassifications		12,887	4,114	(16,675)
Amounts reclassified from OCI		(8,625)	0	0
Ending balance		$ (157,875)	(162,137)	(166,251)
Foreign Currency Items [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Adoption of ASU 2018-02 [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ (1,220)
Ending balance				$ (1,220)

[1] Cash Flow Hedges and Pension Items are net of tax.