Earnings Per Share (Details Textual) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Earnings and Dividends Per Share (Textual) [Abstract]
Forward equity agreement entered, included in the computation of diluted EPS		19,000
Senior Convertible Notes due 2040 [Member]
Earnings and Dividends Per Share (Textual) [Abstract]
Senior Convertible Notes Convertible to common Shares price	16.08
Stock options [Member]
Earnings and Dividends Per Share (Textual) [Abstract]
Options to purchase common shares not included in the computation of diluted EPS	2,900,000
Options to purchase common shares included in the computation of diluted EPS		3,400,000
Warrants [Member]
Earnings and Dividends Per Share (Textual) [Abstract]
Warrants to purchase common shares included in the computation of diluted EPS		10,000,000
Forward Equity [Member]
Earnings and Dividends Per Share (Textual) [Abstract]
Forward Equity Agreement Entered, not included in the computation of diluted EPS	18,975,000
Forward equity agreement entered, included in the computation of diluted EPS		9,500,000