Condensed Consolidated Statements of Changes in Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2012	$ 328,164	$ 118,737	$ 341,586	$ 1,165,952	$ (1,248,377)	$ (49,734)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of unvested shares	512	450	469	0	(407)	0
Net tax effect of stock options exercised and release of unvested shares	(2,606)	0	(2,606)	0	0	0
Stock-based compensation	5,744	0	5,744	0	0	0
Dividends paid ($0.085 and $0.255 per share for three months ended March 31, 2014 and twelve months ended December 31, 2013, respectively)	(16,121)	0	0	(16,121)	0	0
Treasury stock issued	37	0	(98)	0	135	0
Purchase of treasury stock	(1,662)	0	0	0	(1,662)	0
Net income	13,370	0	0	13,370	0	0
Other comprehensive income (loss)	21,616	0	0	0	0	21,616
Balance at Dec. 31, 2013	349,054	119,187	345,095	1,163,201	(1,250,311)	(28,118)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of unvested shares	(347)	292	(63)	0	(576)	0
Net tax effect of stock options exercised and release of unvested shares	(875)	0	(875)	0	0	0
Stock-based compensation	1,288	0	1,288	0	0	0
Dividends paid ($0.085 and $0.255 per share for three months ended March 31, 2014 and twelve months ended December 31, 2013, respectively)	(5,377)	0	0	(5,377)	0	0
Purchase of treasury stock	(175)	0	0	0	(175)	0
Net income	1,845	0	0	1,845	0	0
Other comprehensive income (loss)	739	0	0	0	0	739
Balance at Mar. 31, 2014	$ 346,152	$ 119,479	$ 345,445	$ 1,159,669	$ (1,251,062)	$ (27,379)