Fair Value of Financial Instruments (Fair Value, by Balance Sheet Grouping) (Details) - Level 3 - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Mortgage notes payable | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	$ 171,998	$ 172,242
Mortgage notes payable | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	173,315	174,468
Credit facility | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	635,000	635,000
Credit facility | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	637,865	651,579
Preferred Equity Investment | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	0	35,100
Preferred Equity Investment | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	$ 0	$ 34,800