Derivatives (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Series F Preferred Stock [Member]	Dec. 31, 2011 Series F Preferred Stock [Member]	Oct. 31, 2008 Series F Preferred Stock [Member]
Derivatives (Textual) [Abstract]
Minimum fixed coupon rate of preferred stock			2.375%
Number of years of U.S treasury rate one			30 years
Number of years of U.S treasury rate two			10 years
LIBOR rate			3 month LIBOR
New coupon rate of preferred stock			5.415%
Notional value of interest rate swap agreement					$ 50,000
Treasury Rate			5.2175%
Outstanding payable due on Series F Agreement			292	280
Derivatives (Additional Textual) [Abstract]
Unrealized market to market loss on interest rate protection agreement	0
Amortization Reclassified from OCI into Income	2,308
Unrealized mark to market gain on interest rate protection agreement	124	44
Settlements payments of market to market gains or losses	$ 292	$ 99
Number of years of Long dated Treasuries	30 years