Debt And Lines Of Credit , Table - Schedule of debt and lines of credit (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014 Rate	Dec. 31, 2013 Rate
Debt Instrument [Line Items]
Debt	$ 1,407,317	$ 1,311,437
Debt weighted average to maturity, years	7 years 1 month 6 days	7 years 2 months 12 days
Weighted average interest rate	5.10%	5.00%
Collateralized term loans - CMBS [Member]
Debt Instrument [Line Items]
Debt	641,215	644,844
Debt weighted average to maturity, years	5 years 7 months 6 days	6 years 1 month 6 days
Weighted average interest rate	5.40%	5.40%
Collateralized term loans - FNMA [Member]
Debt Instrument [Line Items]
Debt	363,664	366,019
Debt weighted average to maturity, years	7 years 7 months 6 days	8 years 1 month 6 days
Weighted average interest rate	3.10%	3.60%
Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Debt	1,100,000
Aspen Series B3 Preferred Operating Partnership Units [Member]
Debt Instrument [Line Items]
Debt	47,022	47,022
Debt weighted average to maturity, years	7 years 4 months 24 days	7 years 7 months 6 days
Weighted average interest rate	6.90%	6.90%
Secured borrowing [Member]
Debt Instrument [Line Items]
Debt weighted average to maturity, years	13 years 10 months 24 days	13 years 6 months
Weighted average interest rate	10.50%	10.70%
Mortgage notes, other [Member]
Debt Instrument [Line Items]
Debt	141,309	143,042
Debt weighted average to maturity, years	5 years 6 months	6 years
Weighted average interest rate	4.60%	4.60%
Northwestern Mutual Life Insurance Company [Member] | Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Debt	98,447	0
Debt weighted average to maturity, years	11 years 7 months 6 days
Weighted average interest rate	4.20%
Carrying Value [Member] | Secured borrowing [Member]
Debt Instrument [Line Items]
Debt	$ 115,660	$ 110,510