Fair Value of Financial Instruments Carrying Amount and Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Secured Debt | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	$ 952,174	$ 1,044,682
Secured Debt | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	990,296	1,116,162
Line of Credit | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	93,000	0
Line of Credit | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	$ 93,000	$ 0