Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Preferred Stock, Value, Issued	$ 0	$ 0
Preferred Stock, Shares Authorized	9,945,539	9,945,539
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	41,674,652	41,596,655
Common Stock, Shares, Outstanding	41,674,652	41,596,655
6.75% Series C Cumulative Redeemable Perpetual Preferred Stock [Domain]
Preferred Stock, Value, Issued	$ 136,144	$ 136,144
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