Condensed Consolidated Statements of Changes in Equity (USD $) In Thousands, unless otherwise specified	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2013	$ 119,187	$ 345,095	$ 1,163,201	$ (1,250,311)	$ (28,118)	$ 349,054
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of unvested shares	420	(151)		(750)		(481)
Net tax effect of stock options exercised and release of unvested shares		(1,993)				(1,993)
Stock-based compensation		4,055				4,055
Dividends paid ($ 0.085 and $0.34 per share for the three months ended March 31, 2015 and twelve months ended December 31, 2014, respectively)			(21,485)			(21,485)
Treasury stock issued		(767)		1,307		540
Purchase of treasury stock				(7,894)		(7,894)
Net income			23,991			23,991
Other comprehensive loss					(19,111)	(19,111)
Balance at Dec. 31, 2014	119,607	346,239	1,165,707	(1,257,648)	(47,229)	326,676
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of unvested shares	186	25		(295)		(84)
Net tax effect of stock options exercised and release of unvested shares		(1,168)				(1,168)
Stock-based compensation		1,316				1,316
Dividends paid ($ 0.085 and $0.34 per share for the three months ended March 31, 2015 and twelve months ended December 31, 2014, respectively)			(5,323)			(5,323)
Treasury stock issued		(178)		241		63
Net income			1,615			1,615
Other comprehensive loss					(680)	(680)
Balance at Mar. 31, 2015	$ 119,793	$ 346,234	$ 1,161,999	$ (1,257,702)	$ (47,909)	$ 322,415