Statement of Changes in Stockholders’ Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Common Stock Held in Treasury	Accumulated Other Comprehensive Income/(Loss)	Total
Balance at Dec. 31, 2015	$ 523	$ 239,090	$ 571,626	$ (336,923)	$ (19,495)	$ 454,821
Increase (Decrease) in Stockholders' Equity
Net income (loss)			(25,918)			(25,918)
Other comprehensive (loss) income					(14,482)	(14,482)
Issuance of common stock in connection with employee stock option exercises and for restricted stock unit awards	1	(16,600)		19,237		2,638
Issuance of common stock for the employee stock purchase plan	1	1,320				1,321
Purchase of common stock for treasury				(22,112)		(22,112)
Dividends declared on common stock		4	(9,358)	111		(9,243)
Shares withheld for net settlements of share-based awards				(6,795)		(6,795)
Share-based compensation		24,934				24,934
Balance at Dec. 31, 2016	525	248,748	536,350	(346,482)	(33,977)	405,164
Increase (Decrease) in Stockholders' Equity
Net income (loss)			(39,440)			(39,440)
Other comprehensive (loss) income					12,580	12,580
Issuance of common stock in connection with employee stock option exercises and for restricted stock unit awards	1	(20,749)		21,026		278
Issuance of common stock for the employee stock purchase plan		1,098				1,098
Purchase of common stock for treasury				(16,933)		(16,933)
Dividends declared on common stock		15	(9,310)	101		(9,194)
Shares withheld for net settlements of share-based awards				(10,779)		(10,779)
Share-based compensation		20,238				20,238
Cumulative effect of accounting change		866	(643)			223
Balance at Dec. 31, 2017	526	250,216	486,957	(353,067)	(21,397)	363,235
Increase (Decrease) in Stockholders' Equity
Net income (loss)			691			691
Other comprehensive (loss) income					(11,403)	(11,403)
Issuance of common stock in connection with employee stock option exercises and for restricted stock unit awards	2	(20,738)		22,093		1,357
Issuance of common stock for the employee stock purchase plan		1,040				1,040
Purchase of common stock for treasury				(5,814)		(5,814)
Dividends declared on common stock		25	(9,254)	89		(9,140)
Shares withheld for net settlements of share-based awards				(11,011)		(11,011)
Share-based compensation		29,762				29,762
Cumulative effect of accounting change			(46)			(46)
Balance at Dec. 31, 2018	$ 528	$ 260,305	$ 478,348	$ (347,710)	$ (32,800)	$ 358,671