CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Beginning balance at Dec. 31, 2018	$ 571,383	$ 363,425	$ (2,033)	$ 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
Cumulative effect adjustment upon adoption of ASU | ASU 2016-02		93		93
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	363,425	(2,033)	932,775
Beginning balance (in shares) at Dec. 31, 2018	54,893
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)				13,054
Other comprehensive income (loss)				(3,114)
Ending balance at Jun. 30, 2019	$ 579,250	376,572	(5,147)	950,675
Ending balance (in shares) at Jun. 30, 2019	55,079
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
Beginning balance at Dec. 31, 2019	$ 587,017	368,221	(5,294)	$ 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)
Cumulative effect adjustment upon adoption of ASU | ASU 2016-13		(575)		(575)
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	368,221	(5,294)	$ 949,944
Beginning balance (in shares) at Dec. 31, 2019	55,213			55,213
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)				$ (22,212)
Other comprehensive income (loss)				(7,019)
Ending balance at Jun. 30, 2020	$ 595,726	345,434	(12,313)	$ 928,847
Ending balance (in shares) at Jun. 30, 2020	55,481			55,481
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			55,481