Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Assets:
Land	$ 40,131	$ 1,800
Building and improvements	137,216	21,359
Less: accumulated depreciation	(774)	(50)
Total real estate investments, net	176,573	23,109
Cash and cash equivalents	48,993	105,402
Investment in joint ventures	49,920	72,742
Servicing advances receivable	14,604	0
Retained CDO bonds	7,645	0
Assets held-for-sale, net (includes consolidated VIEs of $0 and $1,913,353, respectively)	0	1,952,264
Tenant and other receivables, net	12,521	4,123
Acquired lease assets, net of accumulated amortization of $556 and $42	13,602	4,386
Deferred costs, net of accumulated amortization of $6 and $2,033	467	415
Other assets	5,579	6,395
Total assets	329,904	2,168,836
Liabilities and Equity (Deficit):
Mortgage notes payable	48,714	0
Accounts payable and accrued expenses	10,363	8,908
Dividends payable	34,019	30,438
Deferred revenue	488	33
Below-market lease liabilities, net of accumulated amortization of $121 and $4	4,020	458
Liabilities related to assets held-for-sale (includes consolidated VIEs of $0 and $2,374,516, respectively)	0	2,380,162
Other liabilities	1,032	665
Total liabilities	98,636	2,420,664
Commitments and contingencies	0	0
Equity (deficit):
Series A cumulative redeemable preferred stock, par value $0.001, liquidation preference $88,146, 4,600,000 shares authorized, 3,525,822 shares issued and outstanding at June 30, 2013 and December 31, 2012.	85,235	85,235
Additional paid-in-capital	1,103,216	1,102,227
Accumulated other comprehensive loss	183	(95,265)
Accumulated deficit	(958,286)	(1,344,989)
Total Gramercy Property Trust Inc. stockholders' equity (deficit)	230,407	(252,731)
Non-controlling interest	861	903
Total equity (deficit)	231,268	(251,828)
Total liabilities and equity (deficit)	329,904	2,168,836
Common Class A [Member]
Equity (deficit):
Common stock Value	55	57
Total equity (deficit)	55	57
Common Class B [Member]
Equity (deficit):
Common stock Value	2	2
Total equity (deficit)	2	2
Common Class B Two [Member]
Equity (deficit):
Common stock Value	2	2
Total equity (deficit)	$ 2	$ 2