Preferred Stock (Details) (USD $)	3 Months Ended	0 Months Ended	1 Months Ended	3 Months Ended	0 Months Ended		3 Months Ended	0 Months Ended
	Mar. 31, 2013	Jan. 07, 2014 Series A Cumulative Redeemable Perpetual Preferred Stock [Member]	Feb. 21, 2013 Series A Cumulative Redeemable Perpetual Preferred Stock [Member]	Mar. 31, 2014 Series A Cumulative Redeemable Perpetual Preferred Stock [Member]	Jan. 07, 2014 Series B Cumulative Redeemable Perpetual Preferred Stock [Member]	Aug. 01, 2013 Series B Cumulative Redeemable Perpetual Preferred Stock [Member]	Mar. 31, 2014 Series B Cumulative Redeemable Perpetual Preferred Stock [Member]	Apr. 09, 2014 Subsequent Event [Member] Series A Cumulative Redeemable Perpetual Preferred Stock [Member]	Apr. 09, 2014 Subsequent Event [Member] Series B Cumulative Redeemable Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock issued			250,000			316,250
Preferred stock, dividend rate			9.50%			9.00%
Preferred stock, par value			$ 1.00			$ 1.00
Preferred stock, liquidation preference per share			$ 100.00			$ 100.00
Shares sold pursuant to over-allotment option granted to underwriters for offering						41,250
Preferred stock, dividend declared		$ 2.375			$ 2.25			$ 2.375	$ 2.25
Accumulated unpaid dividends				$ 0			$ 0
Preferred stock, redemption date				Apr. 30, 2018			Oct. 30, 2018
Cash redemption price (in dollars per share)				$ 100.00			$ 100.00
Net proceeds from the issuance of preferred stock	23,438,000			23,400,000			30,000,000
Underwriter discounts and related costs				$ 1,600,000			$ 1,600,000
Period after change of control to redeem shares				120 days			120 days