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, 2010	$ 437,823	$ 118,296	$ 336,795	$ 1,252,438	$ (1,236,024)	$ (33,682)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of un-vested shares	520	191	522	0	(193)	0
Net tax effect of stock options exercised and release of unvested shares	(959)	0	(959)	0	0	0
Stock-based compensations	4,988	0	4,988	0	0	0
Dividends paid ($0.255, $0.43, and $0.32 per share at December 31, 2013, December 31, 2012, and December 31, 2011 respectively)	(20,370)	0	0	(20,370)	0	0
Treasury stock issued	159	0	(197)	0	356	0
Purchase of treasury stock	(8,363)	0	0	0	(8,363)	0
Net income	44,198	0	0	44,198	0	0
Other comprehensive income (loss)	(11,641)	0	0	0	0	(11,641)
Balance at Dec. 31, 2011	446,355	118,487	341,149	1,276,266	(1,244,224)	(45,323)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options and release of un-vested shares	455	250	410	0	(205)	0
Net tax effect of stock options exercised and release of unvested shares	(3,082)	0	(3,082)	0	0	0
Stock-based compensations	3,412	0	3,412	0	0	0
Dividends paid ($0.255, $0.43, and $0.32 per share at December 31, 2013, December 31, 2012, and December 31, 2011 respectively)	(26,961)	0	0	(26,961)	0	0
Treasury stock issued	151	0	(303)	0	454	0
Purchase of treasury stock	(4,402)	0	0	0	(4,402)	0
Net income	(83,353)	0	0	(83,353)	0	0
Other comprehensive income (loss)	(4,411)	0	0	0	0	(4,411)
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 un-vested 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 compensations	5,744	0	5,744	0	0	0
Dividends paid ($0.255, $0.43, and $0.32 per share at December 31, 2013, December 31, 2012, and December 31, 2011 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)