Fair Value of Financial Instruments (Fair Value, by Balance Sheet Grouping) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Mortgages Notes Payable [Member] Fair Value, Inputs, Level 3 [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member]	Dec. 31, 2012 Mortgages Notes Payable [Member] Fair Value, Inputs, Level 3 [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member]	Mar. 31, 2013 Mortgages Notes Payable [Member] Fair Value, Inputs, Level 3 [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2012 Mortgages Notes Payable [Member] Fair Value, Inputs, Level 3 [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Mar. 31, 2013 Senior Secured Credit Facility [Member] Fair Value, Inputs, Level 3 [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member]	Dec. 31, 2012 Senior Secured Credit Facility [Member] Fair Value, Inputs, Level 3 [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member]	Mar. 31, 2013 Senior Secured Credit Facility [Member] Fair Value, Inputs, Level 3 [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2012 Senior Secured Credit Facility [Member] Fair Value, Inputs, Level 3 [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Mar. 31, 2013 Unsecured Debt [Member] Fair Value, Inputs, Level 3 [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member]	Dec. 31, 2012 Unsecured Debt [Member] Fair Value, Inputs, Level 3 [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member]	Mar. 31, 2013 Unsecured Debt [Member] Fair Value, Inputs, Level 3 [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2012 Unsecured Debt [Member] Fair Value, Inputs, Level 3 [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 1 [Member]	Mar. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Mar. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 2 [Member]	Mar. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Mar. 31, 2012 Interest Rate Swap [Member] Fair Value, Measurements, Recurring [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 1 [Member]	Mar. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Mar. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 2 [Member]	Mar. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Estimate of Fair Value, Fair Value Disclosure [Member]	Mar. 31, 2012 Preferred Stock and Senior Notes [Member] Fair Value, Measurements, Recurring [Member] Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure			$ 265,118	$ 265,118	$ 273,766	$ 271,056	$ 0	$ 124,604	$ 0	$ 124,604	$ 640,000	$ 0	$ 640,000	$ 0
Investment securities, at fair value	4	41,654																					41,654	4	0	0	0	0	41,654	4
Derivative Financial Instruments, Liabilities, Fair Value Disclosure															$ 0	$ 0	$ 0	$ 0	$ (3,830)	$ (5,012)	$ (3,830)	$ (5,012)