Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury stock [Member]	Accumulated other comprehensive income, net [Member]	Total
Balance in the beginning at Dec. 31, 2015	$ 513	$ 997,926	$ 38,670	$ (419,660)	$ 95	$ 617,544
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			251			251
Stock-based compensation		929				929
Issuance under purchase and equity compensation plans, including (gain) loss on reissuance of treasury stock		(1,612)		1,806		194
Repurchase of shares				(21,941)		(21,941)
Cash dividends declared			(1,512)			(1,512)
Other comprehensive income (loss)					8,458	8,458
Balance in the ending at Mar. 31, 2016	513	997,243	37,409	(439,795)	8,553	603,923
Balance in the beginning at Dec. 31, 2016	514	984,087	55,454	(502,104)	(1,762)	536,189
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			8,258			8,258
Stock-based compensation		902				902
Issuance under purchase and equity compensation plans, including (gain) loss on reissuance of treasury stock		(11,314)		5,577		(5,737)
Cash dividends declared			(1,900)			(1,900)
Warrant exercise		(1,933)		1,933
Other comprehensive income (loss)					(94)	(94)
Balance in the ending at Mar. 31, 2017	$ 514	$ 971,742	$ 61,812	$ (494,594)	$ (1,856)	$ 537,618