Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Preferred Stock, Value, Issued	$ 0	$ 0
8.034% Series A Cumulative Redeemable Perpetual Preferred Stock, par value		$ 0.01
8.034% Series A Cumulative Redeemable Perpetual Preferred Stock, shares authorized		8,000,000
8.034% Series A Cumulative Redeemable Perpetual Preferred Stock, shares issued		8,000,000
8.034% Series A Cumulative Redeemable Perpetual Preferred Stock, shares outstanding		8,000,000
Preferred Stock, Shares Authorized	7,391,304	2,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	100,000,000	100,000,000
Common Stock, Shares, Issued	41,431,656	41,078,200
Common Stock, Shares, Outstanding	41,431,656	41,078,200
8.034% Series A Cumulative Redeemable Perpetual Preferred Stock
Preferred Stock, Value, Issued	63,856	0
Preferred Stock, Shares Authorized	2,554,235
Preferred stock, issued	2,554,235
Preferred stock, outstanding	2,554,235
Preferred Stock, Par or Stated Value Per Share	$ 0.01
6.75% Series C Cumulative Redeemable Perpetual Preferred Stock [Domain]
Preferred Stock, Value, Issued	$ 136,144	$ 0
Preferred Stock, Shares Authorized	54,461
Preferred stock, issued	54,458
Preferred stock, outstanding	54,458
Preferred Stock, Par or Stated Value Per Share	$ 0.01