Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Amounts attributable to common stockholders:
Income from continuing operations	$ 10,834	$ 103,435	$ 82,029	$ 243,447
Income (loss) from discontinued operations	(20,067)	(3,812)	(23,756)	14,846
Net Income (Loss) Available to Common Stockholders, Basic	(9,233)	99,623	58,273	258,293
Preferred Stock Dividends, Income Statement Impact	(13)	(13)	(23)	(26)
Income attributable to common stockholders (numerator for basic EPS)	$ (9,246)	$ 99,610	$ 58,250	$ 258,267
Denominator (in thousands):
Weighted average shares used in basic EPS	201,567	200,252	201,342	200,091
Effect of dilutive shares:
Incremental Common Shares Attributable to Conversion of Preferred Stock	2	2	2	2
Incremental Common Shares Attributable to Conversion of Preference Stock	387	398	390	399
Incremental Common Shares Attributable to Share-based Payment Arrangements	847	459	646	407
Weighted-average shares used in diluted EPS	202,803	201,111	202,380	200,899
Income from continuing operations	$ 0.05	$ 0.52	$ 0.41	$ 1.22
Income (loss) from discontinued operations	$ (0.10)	$ (0.02)	$ (0.12)	$ 0.07
Net income	$ (0.05)	$ 0.50	$ 0.29	$ 1.29
Diluted earnings per share:
Income from continuing operations	$ 0.05	$ 0.51	$ 0.41	$ 1.21
Income (loss) from discontinued operations	$ (0.10)	$ (0.02)	$ (0.12)	$ 0.07
Net income	$ (0.05)	$ 0.50	$ 0.29	$ 1.29
Anti-dilutive shares (in thousands):
Anti-dilutive shares not used in calculating diluted weighted-average shares	12,673	13,737	12,881	14,517