Notes Payable - Deferred Financing Fees and Interest Expense (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 29, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Deferred Financing Fees
Financing costs incurred and paid				$ 85	$ 4,908
Loss on extinguishment of debt				259	2
Interest incurred and expensed
Interest expense on debt and capital lease obligations		$ 11,966	$ 15,711	37,560	48,536
(Gain) loss on derivatives, net		(1,374)	2	7,810	12
Amortization of deferred financing fees		544	692	1,648	2,472
Total interest incurred and expensed on debt and capital lease obligations		$ 11,136	$ 16,405	47,018	$ 51,020
Boston Park Plaza mortgage payable
Deferred Financing Fees
Accelerated amortization of deferred financing fees	$ 100
Unsecured Term Loan 2 and Credit Facility
Deferred Financing Fees
Financing costs incurred and paid				$ 100