Preferred Stock (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Class of Stock [Line Items]
Preferred stock, dividend rate (in hundredths)	9.50%
Preferred stock, par value (in dollars per share)	$ 1.00
Net proceeds from the issuance of preferred stock	$ 23,438,000	$ 0
Series A Cumulative Redeemable Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock issued (in shares)	250,000
Preferred stock, dividend rate (in hundredths)	9.50%
Preferred stock, par value (in dollars per share)	$ 1
Preferred stock, liquidation preference per share (in dollars per share)	$ 100
Preferred stock, dividend declared (in dollars per share)	$ 1.79
Accumulated unpaid dividends	0
Number of dividend payments threshold to increase dividend rate	2
Percentage of dividend increase in case of non payment (in hundredths)	2.00%
Increase in dividend per share in case of non payment (in dollars per share)	$ 2
Number of consecutive dividend payment dates to reset original dividend rate	3
Preferred stock, redemption date	Apr. 30, 2018
Preferred stock, cash redemption price per share (in dollars per share)	$ 100
Net proceeds from the issuance of preferred stock	23,438,000
Underwriter discounts and related costs	$ 1,600,000
Series A Cumulative Redeemable Perpetual Preferred Stock [Member] | Maximum [Member]
Class of Stock [Line Items]
Preferred stock, dividend rate (in hundredths)	19.00%