Consolidated Statements Of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Retained Earnings (Deficit)	Retained Earnings (Deficit) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment
Beginning balance at Dec. 31, 2017	$ 477,174	$ 6,780	$ 8,984	$ 352,500	$ 135,486	$ 9,110	$ (19,796)	$ (2,330)
Beginning balance (in shares) at Dec. 31, 2017			29,953
Net loss	(63,146)				(63,146)
Foreign currency translation adjustment, net of tax	(12,164)						(12,164)
Foreign currency hedge, net of tax	496						496
Defined benefit pension plans, net of tax	(598)						(598)
Reclassification of convertible debt embedded derivative, net of tax	37,698			37,698
Non-cash compensation	12,256			12,256
Vesting of stock awards (in shares)			231
Vesting of stock awards	(1,396)		$ 69	(1,465)
Ending balance at Dec. 31, 2018	457,100	(360)	$ 9,053	400,989	81,450	(360)	(34,392)
Ending balance (in shares) at Dec. 31, 2018			30,184
Net loss	(32,417)				(32,417)
Foreign currency translation adjustment, net of tax	4,258						4,258
Foreign currency hedge, net of tax	213						213
Defined benefit pension plans, net of tax	(269)						(269)
Non-cash compensation	10,055			10,055
Vesting of stock awards (in shares)			335
Vesting of stock awards	(1,910)		$ 100	(2,010)
Ending balance at Dec. 31, 2019	436,670	$ (1,035)	$ 9,153	409,034	48,673	$ (1,035)	(30,190)
Ending balance (in shares) at Dec. 31, 2019			30,519
Net loss	(237,203)				(237,203)
Foreign currency translation adjustment, net of tax	3,359			2			3,357
Foreign currency hedge, net of tax	(904)						(904)
Defined benefit pension plans, net of tax	59						59
Non-cash compensation	6,307			6,307
Vesting of stock awards (in shares)			355
Vesting of stock awards	(989)		$ 104	(1,093)
Extinguishment of convertible debt	(14,044)			(14,044)
Issuance of warrant, net	22,383			22,383
Ending balance at Dec. 31, 2020	$ 214,603		$ 9,257	$ 422,589	$ (189,565)		$ (27,678)
Ending balance (in shares) at Dec. 31, 2020			30,874