CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Retained Earnings Reclassify upon adoption of ASU	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Reclassify upon adoption of ASU	Total
Beginning balance at Dec. 31, 2018	$ 571,383	$ 93	$ 363,425	$ (2,033)	$ 93	$ 932,775
Beginning balance (in shares) at Dec. 31, 2018	54,893
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			6,195			6,195
Other comprehensive income (loss)				(2,515)		(2,515)
Stock-based compensation expense	$ 1,766					1,766
Options exercised	$ 1,365					1,365
Options exercised (in shares)	95
Issuance of common stock under Employee Stock Purchase Plan	$ 432					432
Issuance of common stock under Employee Stock Purchase Plans (in shares)	7
Ending balance at Mar. 31, 2019	$ 574,946		369,713	(4,548)		940,111
Ending balance (in shares) at Mar. 31, 2019	54,995
Beginning balance at Dec. 31, 2018	$ 571,383	93	363,425	(2,033)	93	932,775
Beginning balance (in shares) at Dec. 31, 2018	54,893
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)						9,656
Other comprehensive income (loss)						(6,061)
Ending balance at Sep. 30, 2019	$ 584,161		373,174	(8,094)		949,241
Ending balance (in shares) at Sep. 30, 2019	55,208
Beginning balance at Mar. 31, 2019	$ 574,946		369,713	(4,548)		940,111
Beginning balance (in shares) at Mar. 31, 2019	54,995
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			6,859			6,859
Other comprehensive income (loss)				(599)		(599)
Stock-based compensation expense	$ 2,523					2,523
Options exercised	$ 1,441					1,441
Options exercised (in shares)	78
Issuance of common stock under Employee Stock Purchase Plan	$ 340					340
Issuance of common stock under Employee Stock Purchase Plans (in shares)	6
Ending balance at Jun. 30, 2019	$ 579,250		376,572	(5,147)		950,675
Ending balance (in shares) at Jun. 30, 2019	55,079
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			(3,398)			(3,398)
Other comprehensive income (loss)				(2,947)		(2,947)
Stock-based compensation expense	$ 2,626					2,626
Options exercised	$ 2,037					2,037
Options exercised (in shares)	120
Issuance of common stock under Employee Stock Purchase Plan	$ 341					341
Issuance of common stock under Employee Stock Purchase Plans (in shares)	12
Shares surrendered in exchange for exercise of stock options	$ (93)					(93)
Shares surrendered in exchange for exercise of stock options (in shares)	(3)
Ending balance at Sep. 30, 2019	$ 584,161		373,174	(8,094)		949,241
Ending balance (in shares) at Sep. 30, 2019	55,208
Beginning balance at Dec. 31, 2019	$ 587,017	(575)	368,221	(5,294)	(575)	$ 949,944
Beginning balance (in shares) at Dec. 31, 2019	55,213					55,213
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			(3,154)			$ (3,154)
Other comprehensive income (loss)				(9,465)		(9,465)
Stock-based compensation expense	$ 2,641					2,641
Options exercised	$ 2,369					2,369
Options exercised (in shares)	174
Issuance of common stock under Employee Stock Purchase Plan	$ 371					371
Issuance of common stock under Employee Stock Purchase Plans (in shares)	13
Shares surrendered in exchange for payment of payroll tax liabilities	$ (866)					(866)
Shares surrendered in exchange for payment of payroll tax liabilities (in shares)	(23)
Shares surrendered in exchange for exercise of stock options	$ (1,467)					(1,467)
Shares surrendered in exchange for exercise of stock options (in shares)	(39)
Ending balance at Mar. 31, 2020	$ 590,065		364,492	(14,759)		939,798
Ending balance (in shares) at Mar. 31, 2020	55,338
Beginning balance at Dec. 31, 2019	$ 587,017	$ (575)	368,221	(5,294)	$ (575)	$ 949,944
Beginning balance (in shares) at Dec. 31, 2019	55,213					55,213
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)						$ (25,221)
Other comprehensive income (loss)						(4,031)
Ending balance at Sep. 30, 2020	$ 600,737		342,425	(9,325)		$ 933,837
Ending balance (in shares) at Sep. 30, 2020	55,538					55,538
Beginning balance at Mar. 31, 2020	$ 590,065		364,492	(14,759)		$ 939,798
Beginning balance (in shares) at Mar. 31, 2020	55,338
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			(19,058)			(19,058)
Other comprehensive income (loss)				2,446		2,446
Stock-based compensation expense	$ 3,197					3,197
Options exercised	$ 2,229					2,229
Options exercised (in shares)	138
Issuance of common stock under Employee Stock Purchase Plan	$ 235					235
Issuance of common stock under Employee Stock Purchase Plans (in shares)	5
Ending balance at Jun. 30, 2020	$ 595,726		345,434	(12,313)		928,847
Ending balance (in shares) at Jun. 30, 2020	55,481
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			(3,009)			(3,009)
Other comprehensive income (loss)				2,988		2,988
Stock-based compensation expense	$ 3,794					3,794
Options exercised	$ 950					950
Options exercised (in shares)	50
Issuance of common stock under Employee Stock Purchase Plan	$ 267					267
Issuance of common stock under Employee Stock Purchase Plans (in shares)	7
Ending balance at Sep. 30, 2020	$ 600,737		$ 342,425	$ (9,325)		$ 933,837
Ending balance (in shares) at Sep. 30, 2020	55,538					55,538