Fair Value of Financial Instruments Schedule of the aggregate carrying value of debt and estimates of fair value (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable and secured term loan and credit facility	$ 1,208,112	$ 978,150
Unsecured loans and notes payable—related parties	0	18,339
Total	1,208,112	996,489
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable and secured term loan and credit facility	1,225,064	1,003,756
Unsecured loans and notes payable—related parties	0	13,818
Total	$ 1,225,064	$ 1,017,574