Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2014	$ 326,676	$ 119,607	$ 346,239	$ 1,165,707	$ (1,257,648)	$ (47,229)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of unvested shares	(84)	186	25		(295)
Net tax effect of stock options exercised and release of unvested shares	(1,168)		(1,168)
Stock-based compensation	1,316		1,316
Dividends paid ($0.26 and $0.34 per share for the three months ended March 31, 2016 and twelve months ended December 31, 2015, respectively)	(5,323)			(5,323)
Treasury stock issued	63		(178)		241
Purchase of treasury stock	0
Net income	1,615			1,615
Other comprehensive income	(680)					(680)
Balance at Mar. 31, 2015	322,415	119,793	346,234	1,161,999	(1,257,702)	(47,909)
Balance at Dec. 31, 2015	140,316	120,147	353,050	973,538	(1,262,859)	(43,560)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of unvested shares	(81)	118	(118)		(81)
Net tax effect of stock options exercised and release of unvested shares	(593)		(593)
Stock-based compensation	563		563
Dividends paid ($0.26 and $0.34 per share for the three months ended March 31, 2016 and twelve months ended December 31, 2015, respectively)	(5,285)			(5,285)
Treasury stock issued	40		(222)		262
Net income	(5,603)			(5,603)
Other comprehensive income	52					52
Balance at Mar. 31, 2016	$ 129,409	$ 120,265	$ 352,680	$ 962,650	$ (1,262,678)	$ (43,508)