Equity (Details Textual) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Preferred Stock Dividend Rate Percentage	8.00%		8.00%
Operating Partnership Units Outstanding	64.9
Accrued Dividends Preferred Stock	$ 2.5
Dividends paid to common and preferred stockholders	10.7	10.6
Preferred stock, liquidation preference per share	$ 25.00		$ 25.00
Maximum shares issue value under market offering program	100.0
Board Of Directors [Member]
Dividend Declared Per Common Share and Operating Partnership Unit	$ 0.165
Parent Company [Member]
Operating Partnership Units Outstanding	64.5
Percentage Of Operating Partnership Units Held	99.30%
Other Partners [Member]
Operating Partnership Units Outstanding	0.4
Percentage Of Operating Partnership Units Held	0.70%
Fair Market Value Of Operating Partnership Units	$ 3.8
Per Unit Fair Market Value Of Operating Partnership Units	$ 8.68
8% Series A Cumulative Redeemable Preferred Stock [Member]
Preferred stock, liquidation preference per share	$ 25.00
Preferred Stock Dividend Rate Per Dollar Amount	$ 2.00
Preferred Stock Redemption Price Per Share	$ 25.00
Series A Preferred Stock [Member]
Dividend Declared Per Preferred Share	$ 0.50