Earnings (Loss) Per Share Data (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings (loss) per common share - Basic:
Income from continuing operations	$ 38,312	$ 37,784	$ 36,281	$ 49,155	$ (57,086)	$ (9,636)	$ 23,745	$ 57,441	$ 161,532	$ 14,464	$ 234,695
Loss from discontinued operations	(7,129)	(9,900)	(37,728)	(19,851)	(8,208)	(93,630)	(12,146)	(6,589)	(74,608)	(120,573)	(22,772)
Net income (loss)	31,183	27,884	(1,447)	29,304	(65,294)	(103,266)	11,599	50,852	86,924	(106,109)	211,923
Common shares (in shares)	111,687,000	112,729,000	113,487,000	114,129,000	114,685,000	115,554,000	117,434,000	117,763,000	113,000,000	116,348,000	117,094,000
Basic earnings per share, continuing operations (per share)	$ 0.34	$ 0.34	$ 0.32	$ 0.43	$ (0.50)	$ (0.08)	$ 0.20	$ 0.49	$ 1.43	$ 0.12	$ 2.00
Basic earnings per share, discontinued operations (per share)	$ (0.06)	$ (0.09)	$ (0.33)	$ (0.17)	$ (0.07)	$ (0.81)	$ (0.10)	$ (0.06)	$ (0.66)	$ (1.04)	$ (0.19)
Earnings Per Share, Basic	$ 0.28	$ 0.25	$ (0.01)	$ 0.26	$ (0.57)	$ (0.89)	$ 0.10	$ 0.43	$ 0.77	$ (0.91)	$ 1.81
Effect of Dilutive Securities [Abstract]
Stock options, warrants and awards									0	0	0
Interest Income Convertible Securities									287	289	284
convertible debentures, common shares (in shares)									1,011,000	275,000	275,000
Stock options, warrants and awards, common shares (in shares)									770,000	304,000	408,000
Diluted EPS [Abstract]
Loss from discontinued operations	(7,129)	(9,900)	(37,728)	(19,851)	(8,208)	(93,630)	(12,146)	(6,589)	(74,608)	(120,573)	(22,772)
Net income plus assumed conversions									87,211	(105,820)	212,207
Diluted shares (in shares)	114,344,000	114,644,000	114,701,000	115,064,000	114,685,000	115,554,000	118,116,000	118,455,000	114,781,000	116,927,000	117,777,000
Diluted earnings per share, continuing operations plus assumed conversions (per share)	$ 0.34	$ 0.33	$ 0.32	$ 0.43	$ (0.50)	$ (0.08)	$ 0.20	$ 0.49	$ 1.41	$ 0.13	$ 2.00
Diluted earnings per share, discontinued operations (per share)	$ (0.06)	$ (0.09)	$ (0.33)	$ (0.17)	$ (0.07)	$ (0.81)	$ (0.10)	$ (0.06)	$ (0.65)	$ (1.03)	$ (0.19)
Diluted earnings per share (per share)	$ 0.27	$ 0.24	$ (0.01)	$ 0.26	$ (0.57)	$ (0.89)	$ 0.10	$ 0.43	$ 0.76	$ (0.91)	$ 1.80
Income from continuing operations plus assumed conversions									$ 161,819	$ 14,753	$ 234,979
Aggregate number of stock options, warrants and awards excluded from the computation of diluted EPS (in shares)									2,600,000	4,600,000	6,200,000
Convertible Subordinated Debt [Member]
Diluted EPS [Abstract]
treasury stock method average share price to include dilutive securities									$ 27.42
Junior Subordinated Convertible Debentures [Member]
Diluted EPS [Abstract]
treasury stock method average share price to include dilutive securities									$ 40.82
3.25% Convertible Senior Debentures, Due 2035 [Member]
Diluted EPS [Abstract]
treasury stock method average share price to include dilutive securities									$ 79.49