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, 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 unvested shares	455	250	410	0	(205)	0
Net tax effect of options exercised and release of unvested shares	(3,082)	0	(3,082)	0	0	0
Stock-based compensation	3,412	0	3,412	0	0	0
Dividends paid ($0.17 per share and $0.43 per share for nine months ended September 30, 2013 and twelve months ended December 31, 2012, 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 (loss)	(83,353)	0	0	(83,353)	0	0
Other comprehensive income	(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 unvested shares	(201)	332	(126)	0	(407)	0
Net tax effect of options exercised and release of unvested shares	(1,951)	0	(1,951)	0	0	0
Stock-based compensation	4,409	0	4,409	0	0	0
Dividends paid ($0.17 per share and $0.43 per share for nine months ended September 30, 2013 and twelve months ended December 31, 2012, respectively)	(10,749)	0	0	(10,749)	0	0
Treasury stock issued	37	0	(98)	0	135	0
Purchase of treasury stock	(1,049)	0	0	0	(1,049)	0
Net income (loss)	6,804	0	0	6,804	0	0
Other comprehensive income	2,346	0	0	0	0	2,346
Balance at Sep. 30, 2013	$ 327,810	$ 119,069	$ 343,820	$ 1,162,007	$ (1,249,698)	$ (47,388)