CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Capital Surplus	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)	Common Stock In Treasury
Beginning Balance at Dec. 31, 2010	$ 128,070	$ 371	$ 173,935	$ 524,678	$ (4,509)	$ (566,405)
Beginning Balance (in shares) at Dec. 31, 2010		37,069,000				(7,076,000)
Net income	231,704			231,704
Other comprehensive income	11				11
Other comprehensive income:
Prior service costs, net of income tax	(711)
Unrealized gain	(102)
Comprehensive Income	231,715
Exercise of stock options and equity awards (shares)						148,000
Exercise of stock options and equity awards	5,286			(4,678)		9,964
Tax benefit from exercise of stock options and equity award vesting	1,169		1,169
Stock-based compensation	10,905		10,905
Common shares repurchased (in shares)	(3,470,000)					(3,470,000)
Common shares repurchased	(248,099)					(248,099)
Issuance of shares for Directors' compensation (in shares)						1,000
Issuance of shares for Directors' compensation	30			1		29
Shares tendered for taxes (in shares)						(9,000)
Shares tendered for taxes	(614)					(614)
Ending Balance at Sep. 30, 2011	128,462	371	186,009	751,705	(4,498)	(805,125)
Ending Balance (in shares) at Sep. 30, 2011		37,069,000				(10,406,000)
Net income	76,048			76,048
Other comprehensive income:
Prior service costs, net of income tax	(237)				(237)
Net actuarial pension loss, net of income tax	(5,520)				(5,520)
Pension settlement loss, net of $470 of income tax	734				734
Unrealized gain	42				42
Comprehensive Income	71,067
Exercise of stock options and equity awards (shares)						7,000
Exercise of stock options and equity awards	313			(78)		391
Tax benefit from exercise of stock options and equity award vesting	21		21
Stock-based compensation	3,543		3,543
Common shares repurchased (in shares)						(570,000)
Common shares repurchased	(34,602)					(34,602)
Shares tendered for taxes	(5)					(5)
Ending Balance at Dec. 31, 2011	168,799	371	189,573	827,675	(9,479)	(839,341)
Ending Balance (in shares) at Dec. 31, 2011		37,069,000				(10,969,000)
Net income	149,933			149,933
Other comprehensive income	509				509
Other comprehensive income:
Prior service costs, net of income tax	(711)
Unrealized gain	(21)
Comprehensive Income	150,442
Exercise of stock options and equity awards (shares)						272,000
Exercise of stock options and equity awards	8,345			(9,062)		17,407
Tax benefit from exercise of stock options and equity award vesting	922		922
Stock-based compensation	12,600		12,600
Common shares repurchased (in shares)	(3,025,700)					(3,026,000)
Common shares repurchased	(207,918)					(207,918)
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)						(22,000)
Shares tendered for taxes	(1,452)					(1,452)
Ending Balance at Sep. 30, 2012	$ 131,775	$ 371	$ 203,095	$ 968,545	$ (8,970)	$ (1,031,266)
Ending Balance (in shares) at Sep. 30, 2012		37,069,000				(13,744,000)