Consolidated Statement Of Shareholders' Equity (Parenthetical)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Series C Preferred Stock [Member]
Preferred stock, dividends percentage rate	8.50%	8.50%
Series D Preferred Stock [Member]
Preferred stock, dividends percentage rate	7.00%	7.00%	7.00%