Preferred Stock (Details Textual) (USD $)				3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Mar. 31, 2012 Series F [Member]	Jan. 23, 2012 Series F [Member]
Class of Stock [Line Items]
Preferred stock, shares issued				44,000
Liquidation preference per share					$ 25,000
Preferred stock, dividend rate, period				Three month LIBOR plus
Preferred stock, dividend rate, variable percentage				4.468%
Maximum period to redeem preferred stock				90 days
Preferred stock, dividend rate, fixed percentage				6.50%
Preferred Stock (Textual) [Abstract]
Number of preferred stock shares authorized	50,000,000	50,000,000
Par value of Preference shares issued and outstanding	$ 1.00		$ 1.00