CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Common Stock in Treasury [Member]
Beginning Balance at Dec. 31, 2011	$ 169,105	$ 371	$ 184,207	$ 833,347	$ (9,479)	$ (839,341)
Beginning Balance (in shares) at Dec. 31, 2011		37,069,000				(10,969,000)
Net income	60,645			60,645
Other comprehensive income, net of income tax	163				163
Equity award vesting and exercises	4,668		(2,399)	(2,116)		9,183
Equity award vesting and exercises (in shares)						145,000
Tax benefit from equity awards	417		417
Stock-based compensation	4,037		4,037
Common shares repurchased (in shares)	(2,097,200)					(2,097,000)
Common shares repurchased	(146,657)					(146,657)
Issuance of shares for Directors' compensation (in shares)						1,000
Issuance of shares for Directors' compensation	37			(1)		38
Shares tendered for taxes (in shares)						(14,000)
Shares tendered for taxes	(914)					(914)
Ending Balance at Mar. 31, 2012	91,501	371	186,262	891,875	(9,316)	(977,691)
Ending Balance (in shares) at Mar. 31, 2012		37,069,000				(12,934,000)
Net income	78,325			78,325
Other comprehensive income, net of income tax	1,386				1,386
Equity award vesting and exercises	3,677		(1,825)	(2,727)		8,229
Equity award vesting and exercises (in shares)						127,000
Tax benefit from equity awards	501		501
Stock-based compensation	12,175		12,175
Common shares repurchased (in shares)						(929,000)
Common shares repurchased	(61,261)					(61,261)
Shares tendered for taxes (in shares)						(8,000)
Shares tendered for taxes	(539)					(539)
Ending Balance at Dec. 31, 2012	125,765	371	197,113	967,473	(7,930)	(1,031,262)
Ending Balance (in shares) at Dec. 31, 2012		37,069,000				(13,744,000)
Net income	(17,271)			(17,271)
Other comprehensive income, net of income tax	95				95
Equity award vesting and exercises	0		(2,948)			2,948
Equity award vesting and exercises (in shares)						59,000
Tax benefit from equity awards	(2,629)		(2,629)
Stock-based compensation	3,093		3,093
Common shares repurchased (in shares)	0
Common shares repurchased	0
Shares tendered for taxes (in shares)						(22,000)
Shares tendered for taxes	(368)					(368)
Ending Balance at Mar. 31, 2013	$ 108,685	$ 371	$ 194,629	$ 950,202	$ (7,835)	$ (1,028,682)
Ending Balance (in shares) at Mar. 31, 2013		37,069,000				(13,707,000)