Unaudited Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands		Total	Common Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2017			29,953
Beginning balance at Dec. 31, 2017		$ 477,174	$ 8,984	$ 352,500	$ 135,486	$ (19,796)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of new accounting principle, net of tax		6,780			6,780
Net income (loss)		(12,264)			(12,264)
Foreign currency translation adjustment, net of tax		(2)				(2)
Foreign currency hedge, net of tax		(315)				(315)
Non-cash compensation		2,420		2,420
Vesting of stock awards (in shares)			34
Vesting of stock awards		(225)	$ 10	(235)
Ending balance (in shares) at Mar. 31, 2018			29,987
Ending Balance at Mar. 31, 2018		473,568	$ 8,994	354,685	130,002	(20,113)
Beginning balance (in shares) at Dec. 31, 2017			29,953
Beginning balance at Dec. 31, 2017		477,174	$ 8,984	352,500	135,486	(19,796)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(67,131)
Ending balance (in shares) at Sep. 30, 2018			30,023
Ending Balance at Sep. 30, 2018		460,544	$ 9,005	399,163	75,135	(22,759)
Beginning balance (in shares) at Mar. 31, 2018			29,987
Beginning balance at Mar. 31, 2018		473,568	$ 8,994	354,685	130,002	(20,113)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(31,341)			(31,341)
Foreign currency translation adjustment, net of tax		(4,041)				(4,041)
Foreign currency hedge, net of tax		580				580
Issuance of convertible debt, net of tax		37,540		37,540
Non-cash compensation		4,585		4,585
Vesting of stock awards (in shares)			32
Vesting of stock awards		0	$ 10	(10)
Ending balance (in shares) at Jun. 30, 2018			30,019
Ending Balance at Jun. 30, 2018		480,891	$ 9,004	396,800	98,661	(23,574)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(23,526)			(23,526)
Foreign currency translation adjustment, net of tax		733				733
Foreign currency hedge, net of tax		82				82
Non-cash compensation		2,408		2,408
Vesting of stock awards (in shares)			4
Vesting of stock awards		(44)	$ 1	(45)
Ending balance (in shares) at Sep. 30, 2018			30,023
Ending Balance at Sep. 30, 2018		460,544	$ 9,005	399,163	75,135	(22,759)
Beginning balance (in shares) at Dec. 31, 2018			30,184
Beginning balance at Dec. 31, 2018		457,100	$ 9,053	400,989	81,450	(34,392)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of new accounting principle, net of tax		(767)			(767)
Net income (loss)		(24,228)			(24,228)
Foreign currency translation adjustment, net of tax		1,809				1,809
Foreign currency hedge, net of tax		210				210
Non-cash compensation		2,434		2,434
Vesting of stock awards (in shares)			63
Vesting of stock awards		(341)	$ 19	(360)
Ending balance (in shares) at Mar. 31, 2019			30,247
Ending Balance at Mar. 31, 2019		436,217	$ 9,072	403,063	56,455	(32,373)
Beginning balance (in shares) at Dec. 31, 2018			30,184
Beginning balance at Dec. 31, 2018		457,100	$ 9,053	400,989	81,450	(34,392)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(25,183)
Ending balance (in shares) at Sep. 30, 2019			30,340
Ending Balance at Sep. 30, 2019		439,659	$ 9,100	408,837	55,824	(34,102)
Beginning balance (in shares) at Mar. 31, 2019			30,247
Beginning balance at Mar. 31, 2019		436,217	$ 9,072	403,063	56,455	(32,373)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		6,102			6,102
Foreign currency translation adjustment, net of tax		1,005				1,005
Foreign currency hedge, net of tax		(188)				(188)
Non-cash compensation		3,648		3,648
Vesting of stock awards (in shares)			46
Vesting of stock awards		(9)	$ 14	(23)
Other	[1]	324			324
Ending balance (in shares) at Jun. 30, 2019			30,293
Ending Balance at Jun. 30, 2019		447,099	$ 9,086	406,688	62,881	(31,556)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(7,057)			(7,057)
Foreign currency translation adjustment, net of tax		(3,014)				(3,014)
Foreign currency hedge, net of tax		468				468
Non-cash compensation		2,588		2,588
Vesting of stock awards (in shares)			47
Vesting of stock awards		(425)	$ 14	(439)
Ending balance (in shares) at Sep. 30, 2019			30,340
Ending Balance at Sep. 30, 2019		$ 439,659	$ 9,100	$ 408,837	$ 55,824	$ (34,102)

[1] Amount reflects a revision of tax effects for the adoption of ASC 842. Further discussion on the effects of adoption are set forth in Note 1.