Gramercy Property Trust 10-Q 31 Jul 18 2018 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 26, 2018
Document Information [Line Items]
Entity Registrant Name	Gramercy Property Trust
Entity Central Index Key	1,297,587
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Trading Symbol	gpt
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		160,795,797
GPT Operating Partnership LP
Document Information [Line Items]
Entity Registrant Name	GPT Operating Partnership LP
Entity Central Index Key	1,708,204
Entity Filer Category	Non-accelerated Filer

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Real estate investments, at cost:
Land	$ 1,008,704	$ 1,023,908
Building and improvements	4,849,168	4,863,916
Less: accumulated depreciation	(410,020)	(333,151)
Total real estate investments, net	5,447,852	5,554,673
Cash and cash equivalents	59,741	30,231
Restricted cash	12,026	12,723
Investment in unconsolidated equity investments	147,282	70,214
Assets held for sale, net	0	402
Tenant and other receivables, net	94,260	88,750
Acquired lease assets, net of accumulated amortization of $265,990 and $220,473	537,824	598,559
Other assets	134,763	100,484
Total assets	6,433,748	6,456,036
Liabilities:
Senior unsecured revolving credit facility	441,773	357,162
Mortgage notes payable, net	499,215	563,521
Total long-term debt, net	2,886,308	2,865,620
Accounts payable and accrued expenses	45,774	59,619
Dividends payable	62,601	61,971
Below market lease liabilities, net of accumulated amortization of $33,302 and $28,978	148,661	166,491
Other liabilities	54,462	50,002
Total liabilities	3,197,806	3,203,703
Commitments and contingencies
Noncontrolling interest in the Operating Partnership	156,293	113,530
Equity:
Common shares, par value $0.01, 160,792,820 and 160,686,822 issued and outstanding at June 30, 2018 and December 31, 2017, respectively	1,608	1,607
Series A cumulative redeemable preferred shares, par value $0.01, liquidation preference $87,500, and 3,500,000 shares authorized, issued and outstanding at June 30, 2018 and December 31, 2017	84,394	84,394
Additional paid-in-capital	4,406,445	4,409,677
Accumulated other comprehensive income	29,125	12,776
Accumulated deficit	(1,442,153)	(1,369,872)
Total shareholders' equity	3,079,419	3,138,582
Noncontrolling interest in other entities	230	221
Total equity	3,079,649	3,138,803
Partners’ Capital:
Accumulated other comprehensive income	29,125	12,776
Total liabilities and equity	6,433,748	6,456,036
Senior unsecured notes, net
Liabilities:
Unsecured debt	496,990	496,785
Senior unsecured term loans
Liabilities:
Unsecured debt	1,448,330	1,448,152
GPT Operating Partnership LP
Real estate investments, at cost:
Land	1,008,704	1,023,908
Building and improvements	4,849,168	4,863,916
Less: accumulated depreciation	(410,020)	(333,151)
Total real estate investments, net	5,447,852	5,554,673
Cash and cash equivalents	59,741	30,231
Restricted cash	12,026	12,723
Investment in unconsolidated equity investments	147,282	70,214
Assets held for sale, net	0	402
Tenant and other receivables, net	94,260	88,750
Acquired lease assets, net of accumulated amortization of $265,990 and $220,473	537,824	598,559
Other assets	134,763	100,484
Total assets	6,433,748	6,456,036
Liabilities:
Senior unsecured revolving credit facility	441,773	357,162
Mortgage notes payable, net	499,215	563,521
Total long-term debt, net	2,886,308	2,865,620
Accounts payable and accrued expenses	45,774	59,619
Dividends payable	62,601	61,971
Below market lease liabilities, net of accumulated amortization of $33,302 and $28,978	148,661	166,491
Other liabilities	54,462	50,002
Total liabilities	3,197,806	3,203,703
Commitments and contingencies
Noncontrolling interest in the Operating Partnership	156,293	113,530
Equity:
Accumulated other comprehensive income	29,125	12,776
Partners’ Capital:
Series A cumulative redeemable preferred units, liquidation preference $87,500, and 3,500,000 units issued and outstanding at June 30, 2018 and December 31, 2017	84,394	84,394
GPT partners’ capital (1,663,870 and 1,650,858 general partner common units and 159,128,950 and 159,035,964 limited partner common units outstanding at June 30, 2018 and December 31, 2017, respectively)	2,965,900	3,041,412
Accumulated other comprehensive income	29,125	12,776
Total GPTOP partners' capital	3,079,419	3,138,582
Noncontrolling interest in other entities	230	221
Total partners’ capital	3,079,649	3,138,803
Total liabilities and equity	6,433,748	6,456,036
GPT Operating Partnership LP | Senior unsecured notes, net
Liabilities:
Unsecured debt	496,990	496,785
GPT Operating Partnership LP | Senior unsecured term loans
Liabilities:
Unsecured debt	$ 1,448,330	$ 1,448,152

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Acquired lease assets, accumulated amortization (in dollars)	$ 265,990	$ 220,473
Below market lease liabilities, accumulated amortization (in dollars)	$ 33,302	$ 28,978
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares issued	160,792,820	160,686,822
Common stock, shares outstanding	160,792,820	160,686,822
Cumulative redeemable preferred stock, shares authorized	10,000,000	10,000,000
Cumulative redeemable preferred stock, shares outstanding	3,500,000
Series A Preferred Stock
Cumulative redeemable preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Cumulative redeemable preferred stock, liquidation preference (in dollars)	$ 87,500	$ 87,500
Cumulative redeemable preferred stock, shares authorized	3,500,000	3,500,000
Cumulative redeemable preferred stock, shares issued	3,500,000	3,500,000
Cumulative redeemable preferred stock, shares outstanding	3,500,000	3,500,000
GPT Operating Partnership LP
Acquired lease assets, accumulated amortization (in dollars)	$ 265,990	$ 220,473
Below market lease liabilities, accumulated amortization (in dollars)	33,302	28,978
Series A cumulative redeemable preferred units, liquidation preference (in dollars)	$ 87,500	$ 87,500
Series A cumulative redeemable preferred units, units issued	3,500,000	3,500,000
Series A cumulative redeemable preferred units, units outstanding	3,500,000	3,500,000
General partners' capital, units issued	1,663,870	1,650,858
Limited partners' capital, units issued	159,128,950	159,035,964
General partners' capital, units outstanding	1,663,870	1,650,858
Limited partners' capital, units outstanding	159,128,950	159,035,964
Noncontrolling Interest | GPT Operating Partnership LP
Limited partners' capital, units outstanding	5,959,858	4,398,935

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Rental revenue	$ 119,177,000	$ 108,261,000	$ 241,422,000	$ 211,543,000
Other income	1,698,000	1,838,000	2,833,000	3,590,000
Total revenues	145,595,000	131,365,000	295,075,000	261,359,000
Operating expenses
Depreciation and amortization	68,479,000	62,176,000	139,995,000	124,393,000
Property operating expenses	26,018,000	23,219,000	53,106,000	46,405,000
General and administrative expenses	8,862,000	9,100,000	18,548,000	17,856,000
Property management expenses	2,616,000	2,435,000	5,158,000	5,519,000
Merger-related expenses	1,945,000	0	1,945,000	0
Total operating expenses	107,920,000	96,930,000	218,752,000	194,173,000
Operating income	37,675,000	34,435,000	76,323,000	67,186,000
Other expenses:
Interest expense	(25,597,000)	(23,239,000)	(51,089,000)	(46,295,000)
Other-than-temporary impairment	0	0	0	(4,081,000)
Portion of impairment recognized in other comprehensive loss	0	0	0	(809,000)
Net impairment recognized in earnings	0	0	0	(4,890,000)
Gain on derivative instruments	14,970,000	0	14,970,000	0
Equity in net income (loss) of unconsolidated equity investments	(1,838,000)	248,000	(2,764,000)	154,000
Gain on extinguishment of debt	83,000	268,000	83,000	60,000
Impairment losses	(4,601,000)	(5,580,000)	(4,601,000)	(18,351,000)
Impairment of goodwill			3,293,000
Income (loss) from continuing operations before provision for taxes	20,692,000	6,132,000	32,922,000	(2,136,000)
Benefit (provision) for taxes	62,000	(147,000)	(559,000)	49,000
Income (loss) from continuing operations	20,754,000	5,985,000	32,363,000	(2,087,000)
Loss from discontinued operations	0	(28,000)	0	(52,000)
Net income (loss) before net gain on disposals	20,754,000	5,957,000	32,363,000	(2,139,000)
Net gain on disposals	4,523,000	2,002,000	20,778,000	19,379,000
Net income	25,277,000	7,959,000	53,141,000	17,240,000
Net (income) loss attributable to noncontrolling interest	(845,000)	113,000	(1,647,000)	(41,000)
Net income attributable to Gramercy Property Trust	24,432,000	8,072,000	51,494,000	17,199,000
Preferred share dividends	(1,558,000)	(1,558,000)	(3,117,000)	(3,117,000)
Net income available to common shareholders	$ 22,874,000	$ 6,514,000	$ 48,377,000	$ 14,082,000
Basic earnings per share:
Net income from continuing operations, after preferred dividends (in usd per share)	$ 0.14	$ 0.04	$ 0.30	$ 0.09
Net income (loss) from discontinued operations (in usd per share)	0	0	0	0
Net income available to common stockholders (in usd per share)	0.14	0.04	0.30	0.09
Diluted earnings per share:
Net income from continuing operations, after preferred dividends (in usd per share)	0.14	0.04	0.30	0.09
Net income (loss) from discontinued operations (in usd per share)	0	0	0	0
Net income available to common stockholders (in usd per share)	$ 0.14	$ 0.04	$ 0.30	$ 0.09
Basic weighted average common shares outstanding (in shares)	160,420,278	148,542,916	160,414,240	144,746,251
Diluted weighted average common shares and common share equivalents outstanding (in shares)	160,433,351	149,914,443	160,425,291	145,965,936
GPT Operating Partnership LP
Revenues
Rental revenue	$ 119,177,000	$ 108,261,000	$ 241,422,000	$ 211,543,000
Other income	1,698,000	1,838,000	2,833,000	3,590,000
Total revenues	145,595,000	131,365,000	295,075,000	261,359,000
Operating expenses
Depreciation and amortization	68,479,000	62,176,000	139,995,000	124,393,000
Property operating expenses	26,018,000	23,219,000	53,106,000	46,405,000
General and administrative expenses	8,862,000	9,100,000	18,548,000	17,856,000
Property management expenses	2,616,000	2,435,000	5,158,000	5,519,000
Merger-related expenses	1,945,000	0	1,945,000	0
Total operating expenses	107,920,000	96,930,000	218,752,000	194,173,000
Operating income	37,675,000	34,435,000	76,323,000	67,186,000
Other expenses:
Interest expense	(25,597,000)	(23,239,000)	(51,089,000)	(46,295,000)
Other-than-temporary impairment	0	0	0	(4,081,000)
Portion of impairment recognized in other comprehensive loss	0	0	0	(809,000)
Net impairment recognized in earnings	0	0	0	(4,890,000)
Gain on derivative instruments	14,970,000	0	14,970,000	0
Equity in net income (loss) of unconsolidated equity investments	(1,838,000)	248,000	(2,764,000)	154,000
Gain on extinguishment of debt	83,000	268,000	83,000	60,000
Impairment losses	(4,601,000)	(5,580,000)	(4,601,000)	(18,351,000)
Income (loss) from continuing operations before provision for taxes	20,692,000	6,132,000	32,922,000	(2,136,000)
Benefit (provision) for taxes	62,000	(147,000)	(559,000)	49,000
Income (loss) from continuing operations	20,754,000	5,985,000	32,363,000	(2,087,000)
Loss from discontinued operations	0	(28,000)	0	(52,000)
Net income (loss) before net gain on disposals	20,754,000	5,957,000	32,363,000	(2,139,000)
Net gain on disposals	4,523,000	2,002,000	20,778,000	19,379,000
Net income	25,277,000	7,959,000	53,141,000	17,240,000
Net loss attributable to noncontrolling interest in other partnerships	0	137,000	0	17,000
Net income attributable to Gramercy Property Trust	25,277,000	8,096,000	53,141,000	17,257,000
Preferred share dividends	(1,558,000)	(1,558,000)	(3,117,000)	(3,117,000)
Net income available to common unitholders	$ 23,719,000	$ 6,538,000	$ 50,024,000	$ 14,140,000
Basic earnings per unit:
Net income from continuing operations, after preferred unit distributions basic (in usd per unit)	$ 0.14	$ 0.04	$ 0.30	$ 0.09
Net income (loss) from discontinued operations, basic (in usd per unit)	0	0	0	0
Net income available to common unitholders, basic (in usd per unit)	0.14	0.04	0.30	0.09
Diluted earnings per unit:
Net income from continuing operations, after preferred unit distributions, diluted (in usd per unit)	0.14	0.04	0.30	0.09
Net income (loss) from discontinued operations, diluted (in usd per unit)	0	0	0	0
Net income available to common unitholders, diluted (in usd per unit)	$ 0.14	$ 0.04	$ 0.30	$ 0.09
Basic weighted average common units outstanding (in units)	166,355,043	149,103,359	165,904,457	145,336,798
Diluted weighted average common units outstanding (in units)	166,368,116	150,474,886	165,915,508	146,556,483
Operating expense reimbursements
Revenues
Reimbursements and fees	$ 22,346,000	$ 19,628,000	$ 45,656,000	$ 39,996,000
Operating expense reimbursements | GPT Operating Partnership LP
Revenues
Reimbursements and fees	22,346,000	19,628,000	45,656,000	39,996,000
Third-party management fees
Revenues
Reimbursements and fees	2,374,000	1,638,000	5,164,000	6,230,000
Third-party management fees | GPT Operating Partnership LP
Revenues
Reimbursements and fees	$ 2,374,000	$ 1,638,000	$ 5,164,000	$ 6,230,000

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income	$ 25,277	$ 7,959	$ 53,141	$ 17,240
Other comprehensive income (loss):
Unrealized gain (loss) on available for sale debt securities	667	1,251	619	(1,569)
Cumulative effect of accounting change	0	0	103	0
Unrealized gain (loss) on derivative instruments	4,990	(2,692)	27,040	1,686
Reclassification of unrealized gain (loss) on terminated derivative instruments into earnings	(11,017)	271	(10,749)	539
Foreign currency translation adjustments	(1,182)	1,101	(664)	1,792
Other comprehensive income (loss)	(6,542)	(69)	16,349	2,448
Comprehensive income	18,735	7,890	69,490	19,688
Net (income) loss attributable to noncontrolling interest	(845)	113	(1,647)	(41)
Other comprehensive (income) loss attributable to noncontrolling interest	(233)	25	464	14
Comprehensive income attributable to Gramercy Property Trust	17,657	8,028	68,307	19,661
GPT Operating Partnership LP
Net income	25,277	7,959	53,141	17,240
Other comprehensive income (loss):
Unrealized gain (loss) on available for sale debt securities	667	1,251	619	(1,569)
Cumulative effect of accounting change	0	0	103	0
Unrealized gain (loss) on derivative instruments	4,990	(2,692)	27,040	1,686
Reclassification of unrealized gain (loss) on terminated derivative instruments into earnings	(11,017)	271	(10,749)	539
Foreign currency translation adjustments	(1,182)	1,101	(664)	1,792
Other comprehensive income (loss)	(6,542)	(69)	16,349	2,448
Comprehensive income	18,735	7,890	69,490	19,688
Net loss attributable to noncontrolling interest in other partnerships	0	137	0	17
Other comprehensive (income) loss attributable to noncontrolling interest	0	25	0	25
Comprehensive income attributable to Gramercy Property Trust	$ 18,735	$ 8,052	$ 69,490	$ 19,730

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Shareholders' Equity (Deficit) and Noncontrolling Interests - USD ($) $ in Thousands	Total	Gramercy Property Trust	Common Shares	Preferred Shares	Additional Paid-In-Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting changes	$ 663	$ 663				$ 103	$ 560
Balance (in shares) at Dec. 31, 2017	160,686,822		160,686,822
Balance at Dec. 31, 2017	$ 3,138,803	3,138,582	$ 1,607	$ 84,394	$ 4,409,677	12,776	(1,369,872)	$ 221
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	51,494	51,494					51,494	0
Change in net unrealized gain on derivative instruments	27,040	27,040				27,040
Change in net unrealized gain on debt securities	619	619				619
Reclassification of unrealized gain on terminated derivative instruments into earnings	(10,749)	(10,749)				(10,749)
Offering costs	(40)	(40)			(40)
Issuance of shares - share purchase plan (in shares)			1,374
Share based compensation - fair value (in shares)			95,223
Share-based compensation - fair value	$ 4,046	4,046	$ 1		4,045
Dividend reinvestment program proceeds (in shares)	3,363		3,363
Dividend reinvestment program proceeds	$ 81	81			81
Conversion of OP Units to commons shares (in shares)			6,038
Conversion of OP Units to common shares	130	130	$ 0		130
Reallocation of noncontrolling interest in the Operating Partnership	(7,448)	(7,448)			(7,448)
Foreign currency translation adjustment	(664)	(664)				(664)		0
Contributions to noncontrolling interest in other partnerships	9						0	9
Dividends on preferred shares	(3,117)	(3,117)					(3,117)
Dividends on common shares	$ (121,218)	(121,218)					(121,218)
Balance (in shares) at Jun. 30, 2018	160,792,820		160,792,820
Balance at Jun. 30, 2018	$ 3,079,649	$ 3,079,419	$ 1,608	$ 84,394	$ 4,406,445	$ 29,125	$ (1,442,153)	$ 230

Condensed Consolidated Stateme7

Condensed Consolidated Statement of Partners' Capital - USD ($) $ in Thousands	Total	GPT Operating Partnership LP	GPT Operating Partnership LPGPTOP	GPT Operating Partnership LPPartners' Interest	GPT Operating Partnership LPSeries A Preferred Units	GPT Operating Partnership LPAccumulated Other Comprehensive Income (Loss)	GPT Operating Partnership LPNoncontrolling Interest
Increase (Decrease) in Partners' Capital [Roll Forward]
Cumulative effect of accounting changes	$ 663	$ 663	$ 663	$ 560		$ 103
Beginning balance (in units) at Dec. 31, 2017				160,686,822
Beginning balance at Dec. 31, 2017		3,138,803	3,138,582	$ 3,041,412	$ 84,394	12,776	$ 221
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	51,494	51,494	51,494	51,494			0
Change in net unrealized gain on derivative instruments	27,040	27,040	27,040			27,040
Change in net unrealized gain on debt securities	619	619	619			619
Reclassification of unrealized gain (loss) on terminated derivative instruments into earnings	(10,749)	(10,749)	(10,749)			(10,749)
Offering costs		(40)	(40)	$ (40)
Issuance of common units resulting from issuance of shares under the share purchase plan (in units)				1,374
Share based compensation - fair value (in units)				95,223
Share-based compensation - fair value		4,046	4,046	$ 4,046
Distribution reinvestment program proceeds (in units)				3,363
Distribution reinvestment program proceeds		81	81	$ 81
Conversion of OP Units to common unit (in units)				6,038
Conversion of OP Units to common units		130	130	$ 130
Reallocation of noncontrolling interest in the Operating Partnership	(7,448)	(7,448)	(7,448)	(7,448)
Foreign currency translation adjustment		(664)	(664)			(664)	0
Contributions to noncontrolling interest in other partnerships	$ 9	9				0	$ 9
Distributions on preferred units		(3,117)	(3,117)	(3,117)
Distributions on common units		$ (121,218)	(121,218)	$ (121,218)
Ending balance (in units) at Jun. 30, 2018		160,792,820		160,792,820			5,959,858
Ending balance at Jun. 30, 2018		$ 3,079,649	$ 3,079,419	$ 2,965,900	$ 84,394	$ 29,125	$ 230

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities:
Net income	$ 53,141	$ 17,240
Adjustments to net cash provided by operating activities:
Depreciation and amortization	139,995	124,393
Amortization of market lease intangibles	(1,705)	(5,227)
Amortization of deferred costs	1,652	1,274
Amortization of discounts and other fees	(1,219)	33
Straight-line rent adjustment	(12,828)	(14,718)
Other-than-temporary impairment on retained bonds	0	4,890
Impairment losses	4,601	18,351
Gain on derivative instruments	(14,970)	0
Net gain on disposals	(20,778)	(19,379)
Distributions received from unconsolidated equity investments	555	689
Equity in net (income) loss of unconsolidated equity investments	2,764	(154)
Gain on extinguishment of debt	(83)	(60)
Amortization of share-based compensation	3,804	4,058
Changes in operating assets and liabilities:
Payment of capitalized leasing costs	(11,453)	(6,008)
Tenant and other receivables	7,347	20,031
Other assets	(488)	(3,125)
Accounts payable and accrued expenses	(6,464)	(14,331)
Other liabilities	4,412	(1,895)
Net cash provided by operating activities	148,283	126,062
Investing Activities:
Capital expenditures	(64,518)	(46,119)
Proceeds from sales of real estate	127,081	207,553
Contributions to unconsolidated equity investments	(46,065)	(7,400)
Acquisition of real estate	(34,722)	(284,689)
Funding of loan investments	(14,756)	0
Proceeds received from loan investments	4,271	0
Net cash used in investing activities	(28,709)	(130,655)
Financing Activities:
Proceeds from unsecured term loan and credit facility	330,179	155,000
Repayment of unsecured term loans and credit facility	(245,000)	(155,000)
Proceeds from mortgage notes payable	0	2,582
Repayment of mortgage notes payable	(63,263)	(58,014)
Offering costs	0	(12,346)
Proceeds from sale of common shares	0	305,763
Payment of deferred financing costs	0	(213)
Proceeds from settlement of forward starting swap	14,970	0
Preferred share dividends paid	(3,117)	(3,117)
Common share dividends paid	(121,175)	(106,377)
Distribution to noncontrolling interest in the Operating Partnership	(3,176)	(205)
Other financing activities	(78)	0
Net cash provided by (used in) financing activities	(90,660)	128,073
Net increase in cash, cash equivalents, and restricted cash	28,914	123,480
Decrease in cash, cash equivalents, and restricted cash related to foreign currency translation	(101)	(78)
Cash, cash equivalents, and restricted cash at beginning of period	42,954	80,433
Cash, cash equivalents, and restricted cash at end of period	71,767	203,835
GPT Operating Partnership LP
Operating Activities:
Net income	53,141	17,240
Adjustments to net cash provided by operating activities:
Depreciation and amortization	139,995	124,393
Amortization of market lease intangibles	(1,705)	(5,227)
Amortization of deferred costs	1,652	1,274
Amortization of discounts and other fees	(1,219)	33
Straight-line rent adjustment	(12,828)	(14,718)
Other-than-temporary impairment on retained bonds	0	4,890
Impairment losses	4,601	18,351
Gain on derivative instruments	(14,970)	0
Net gain on disposals	(20,778)	(19,379)
Distributions received from unconsolidated equity investments	555	689
Equity in net (income) loss of unconsolidated equity investments	2,764	(154)
Gain on extinguishment of debt	(83)	(60)
Amortization of share-based compensation	3,804	4,058
Changes in operating assets and liabilities:
Payment of capitalized leasing costs	(11,453)	(6,008)
Tenant and other receivables	7,347	20,031
Other assets	(488)	(3,125)
Accounts payable and accrued expenses	(6,464)	(14,331)
Other liabilities	4,412	(1,895)
Net cash provided by operating activities	148,283	126,062
Investing Activities:
Capital expenditures	(64,518)	(46,119)
Proceeds from sales of real estate	127,081	207,553
Contributions to unconsolidated equity investments	(46,065)	(7,400)
Acquisition of real estate	(34,722)	(284,689)
Funding of loan investments	(14,756)	0
Proceeds received from loan investments	4,271	0
Net cash used in investing activities	(28,709)	(130,655)
Financing Activities:
Proceeds from unsecured term loan and credit facility	330,179	155,000
Repayment of unsecured term loans and credit facility	(245,000)	(155,000)
Proceeds from mortgage notes payable	0	2,582
Repayment of mortgage notes payable	(63,263)	(58,014)
Offering costs	0	(12,346)
Proceeds from sale of common shares	0	305,763
Payment of deferred financing costs	0	(213)
Proceeds from settlement of forward starting swap	14,970	0
Preferred share dividends paid	(3,117)	(3,117)
Common share dividends paid	(121,175)	(106,377)
Distribution to noncontrolling interest in the Operating Partnership	(3,176)	(205)
Other financing activities	(78)	0
Net cash provided by (used in) financing activities	(90,660)	128,073
Net increase in cash, cash equivalents, and restricted cash	28,914	123,480
Decrease in cash, cash equivalents, and restricted cash related to foreign currency translation	(101)	(78)
Cash, cash equivalents, and restricted cash at beginning of period	42,954	80,433
Cash, cash equivalents, and restricted cash at end of period	$ 71,767	$ 203,835

Business and Organization

Business and Organization	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Organization	Business and Organization Gramercy Property Trust, or the Company or Gramercy, a Maryland real estate investment trust, or REIT, together with its subsidiary, GPT Operating Partnership LP, or the Operating Partnership, is a leading global investor and asset manager of commercial real estate. Gramercy specializes in acquiring and managing high quality, income producing commercial real estate leased to high quality tenants in major markets in the United States and Europe. Gramercy earns revenues primarily through rental revenues on properties that it owns in the United States. The Company also owns unconsolidated equity investments in the United States, Europe, and Asia. The Company's operations are conducted primarily through the Operating Partnership. As of June 30, 2018 , third-party holders of limited partnership interests owned approximately 3.58% of the Operating Partnership. These interests are referred to as the noncontrolling interests in the Operating Partnership. See Note 11 for more information on the Company’s noncontrolling interests. As of June 30, 2018 , the Company’s wholly-owned portfolio consisted of 355 properties comprising 81,134,150 rentable square feet with 96.7% occupancy. As of June 30, 2018 , the Company had ownership interests in 33 properties held in unconsolidated equity investments in the United States and Europe and one property held through the investment in CBRE Strategic Partners Asia. As of June 30, 2018 , the Company managed approximately $2,364,000 of commercial real estate assets, including approximately $1,617,000 of assets in Europe. During the six months ended June 30, 2018 , the Company acquired three properties aggregating 550,522 square feet for a total purchase price of approximately $32,690 and placed one development property into service with 126,722 square feet. During the six months ended June 30, 2018 , the Company sold 14 properties and one land parcel that was part of another asset aggregating 1,890,057 square feet for total gross proceeds of approximately $130,983 . Unless the context requires otherwise, all references to “Company," "Gramercy,” “we,” “our” and “us” mean Gramercy Property Trust and its subsidiaries, including the Operating Partnership and its consolidated subsidiaries. Pending Mergers On May 6, 2018, the Company and the Operating Partnership entered into an Agreement and Plan of Merger, or the Merger Agreement, with BRE Glacier Parent L.P., or Parent, BRE Glacier L.P., or Merger Sub I, and BRE Glacier Acquisition L.P., or Merger Sub II, all of which are affiliates of Blackstone Real Estate Partners VIII L.P., an affiliate of The Blackstone Group L.P. Pursuant to the Merger Agreement, Merger Sub II will merge with and into the Operating Partnership, or the Partnership Merger, and the Company will merge with and into Merger Sub I, or the Company Merger, and, together with the Partnership Merger, the Mergers. Following the Mergers, Merger Sub I and the Operating Partnership will continue as the surviving entities and the separate existence of the Company and Merger Sub II will cease. The Merger Agreement, the Mergers, and the other transactions contemplated thereby were unanimously approved by the Company’s board of trustees. Pursuant to the Merger Agreement, the closing of the Mergers will take place on the third business day after satisfaction of waiver of the conditions to the Merger (other than those conditions that by their nature are to be satisfied or waived at the closing, but subject to the satisfaction or waiver of such conditions) or at such other date as mutually agreed to by the parties to the Merger Agreement; however, Parent may on one or more occasions elect to delay the closing to a date that is on or prior to October 10, 2018. Pursuant to the terms and conditions in the Merger Agreement, each of the Company’s common shares, other than shares owned by Parent, Merger Sub I or any subsidiary of Parent, the Company or Merger Sub I and any award of restricted Company common shares, that is issued and outstanding immediately prior to the effective time of the Company Merger will automatically be converted into the right to receive an amount in cash equal to $27.50 , plus, if the Mergers are consummated after October 15, 2018, a per diem amount of approximately $0.004 for each day from and after such date until, but not including, the closing date, or the Merger Consideration, without interest. Pursuant to the terms and conditions in the Merger Agreement, each of the Company’s 7.125% Series A Preferred Shares, or the Series A Preferred Shares, issued and outstanding immediately prior to the effective time of the Company Merger will be redeemed as of the closing date of the Company Merger through the payment of an amount, without interest, equal to $25.00 plus accrued and unpaid dividends, if any, until, but not including, the closing date. At the effective time of the Partnership Merger, each outstanding Class A Unit of the Operating Partnership, or OP Unit, other than OP Units held by the Company or any of the Company’s subsidiaries or Parent, Merger Sub II, or any of their respective subsidiaries, that is issued and outstanding immediately prior to the effective time of the Partnership Merger will automatically be converted into, and will be cancelled in exchange for, the right to receive an amount in cash equal to the Merger Consideration, without interest, or in lieu of receiving the Merger Consideration, each qualifying holder of an OP Unit may elect to receive one newly created Series B Cumulative Preferred Unit in the surviving partnership for each OP Unit of such holder. Additionally, each unvested unit of limited partnership interest in the Operating Partnership granted by the Company pursuant to its share-based compensation plans, or LTIP Unit, will vest pursuant to its terms on the day prior to the effective time of the Partnership Merger and each vested LTIP Unit (including those that vest on the day prior to the effective time of the Partnership Merger) will be converted into an OP Unit immediately prior to the effective time of the Partnership Merger and treated as an OP Unit as previously described. In addition, each award of restricted common shares and each restricted share unit, or RSU, award that is outstanding immediately prior to the effective time of the Company Merger will be cancelled in exchange for a cash payment in an amount equal to (i) the number of Company common shares subject to the restricted share or RSU award at that time multiplied by (ii) the Merger Consideration, less any applicable withholding taxes. Each option to purchase Company common shares will be cancelled in exchange for a cash payment in an amount equal to (i) the number of Company common shares subject to the option immediately prior to the effective time of the Company Merger multiplied by (ii) the excess (if any) of the Merger Consideration over the per share exercise price applicable to the option, less any applicable withholding taxes. The Merger Agreement contains customary representations, warranties and covenants, including, among others, covenants by the Company to, in all material respects, use commercially reasonable efforts to carry on its business in the ordinary course of business consistent with past practice, subject to certain exceptions, during the period between the execution of the Merger Agreement and the consummation of the Mergers. The obligations of the parties to consummate the Mergers are not subject to any financing condition or the receipt of any financing by Parent, Merger Sub I, or Merger Sub II. The consummation of the Mergers is subject to certain customary closing conditions, including, among others, approval of the Company Merger and the other transactions contemplated by the Merger Agreement by the affirmative vote of the holders of Company common shares entitled to cast not less than a majority of all of the votes entitled to be cast on the matter, or the Company Requisite Vote. The Company will convene a shareholders’ meeting for purposes of obtaining the Company Requisite Vote on August 9, 2018, as described in its definitive proxy statement filed on June 27, 2018. Upon a termination of the Merger Agreement, under certain circumstances, the Company will be required to pay a termination fee to Parent of $138,000 . Upon termination of the Merger Agreement in certain other circumstances, Parent will be required to pay the Company a termination fee up to $414,000 . This description of certain terms of the Merger Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Merger Agreement, a copy of which is included as an exhibit to our definitive proxy statement on Schedule 14A which was filed on June 27, 2018.

Real Estate Investments

Real Estate Investments	6 Months Ended
	Jun. 30, 2018
Real Estate [Abstract]
Real Estate Investments	Real Estate Investments Investments in real estate properties consisted of the following: June 30, 2018 December 31, 2017 Square feet 1 Number of properties Investment Square feet 1 Number of properties Investment Operating properties 2 81,134,150 353 $ 5,828,172 82,146,063 363 $ 5,857,906 Land parcels 2 7,075 2 7,075 Less accumulated depreciation (410,020 ) (333,151 ) Total operating properties and land parcels $ 5,425,227 $ 5,531,830 Development properties 1,653,300 6 22,625 1,630,022 6 22,843 Total 82,787,450 361 $ 5,447,852 83,776,085 371 $ 5,554,673 1. Represents rentable square feet for operating properties and projected rentable square feet upon completion for development properties. 2. Includes development properties that have been completed as of the end of the period. Acquisitions: Real estate acquisition activity for the three and six months ended June 30, 2018 and 2017 was as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Number of operating properties 2 10 3 17 Number of land parcels — 2 — 2 Rentable square feet of operating properties 388,466 2,493,043 550,522 4,750,354 Total purchase price of all acquisitions $ 22,140 $ 177,740 $ 32,690 $ 302,412 The total value of the properties acquired during the three months ended June 30, 2018 was composed of $21,691 of real estate assets and $2,060 of intangible assets, including acquisition costs capitalized for the asset acquisitions. The total value of the properties acquired during the six months ended June 30, 2018 was composed of $31,888 of real estate assets and $2,695 of intangible assets, including acquisition costs capitalized for the asset acquisitions. In addition to the operating property acquisitions noted above, during the six months ended June 30, 2018 the Company also placed into service one development property which comprised 126,722 rentable square feet. Dispositions: Real estate disposition activity for the three and six months ended June 30, 2018 and 2017 was as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Number of properties 1,2 9 10 14 17 Rentable square feet 343,966 1,739,881 1,890,057 2,227,753 Gross proceeds $ 19,971 $ 183,302 $ 130,983 $ 234,985 Impairment of real estate investments related to asset dispositions during the period 3 $ — $ 528 $ — $ 13,299 Net gain on disposals $ 4,523 $ 2,002 $ 20,778 $ 19,379 1. During the three and six months ended June 30, 2018, the Company sold nine and 14 properties, respectively, and also sold a land parcel that was part of another asset. 2. During the three and six months ended June 30, 2017, the Company sold 10 and 17 properties, respectively, as well as two offices that were part of another asset. 3. Although there were no impairments recognized related to assets disposed during the three and six months ended June 30, 2018, as presented in the table, the Company recognized impairments of $1,308 during these periods related to two properties held as of June 30, 2018 that were determined to have non-recoverable declines in value. In addition to the impairments recognized related to assets disposed during the three and six months ended June 30, 2017, as presented in the table, the Company recognized impairments of $5,052 during these periods related to three properties held as of June 30, 2017 that were determined to have non-recoverable declines in value. Intangibles: Intangible assets and liabilities as of June 30, 2018 and December 31, 2017 consisted of the following: Weighted average amortization period (years) June 30, 2018 December 31, 2017 Intangible assets: In-place leases, net of accumulated amortization of $236,602 and $194,836 9.4 $ 490,350 $ 545,782 Above-market leases, net of accumulated amortization of $28,930 and $25,229 7.2 41,700 46,713 Below-market ground rent, net of accumulated amortization of $458 and $408 17.3 5,774 6,064 Total intangible assets $ 537,824 $ 598,559 Intangible liabilities: Below-market leases, net of accumulated amortization of $32,733 and $28,516 39.4 $ 141,929 $ 159,652 Above-market ground rent, net of accumulated amortization of $569 and $462 31.8 6,732 6,839 Total intangible liabilities $ 148,661 $ 166,491 The following table provides the projected amortization expense of the intangible assets and liabilities for the next five years: July 1 to December 31, 2018 2019 2020 2021 2022 Depreciation and amortization expense $ 44,977 $ 81,899 $ 70,915 $ 60,426 $ 47,619 Rental revenue increase $ (3,271 ) $ (2,854 ) $ (3,559 ) $ (3,450 ) $ (5,467 ) The Company recorded $22,983 and $24,167 of amortization of in-place lease intangible assets as part of depreciation and amortization expense for the three months ended June 30, 2018 and 2017 , respectively. The Company recorded $49,142 and $48,339 of amortization of in-place lease intangible assets as part of depreciation and amortization expense for the six months ended June 30, 2018 and 2017 , respectively. The Company recorded $1,433 and $4,756 of amortization of market lease intangible assets and liabilities as an increase to rental revenue for the three months ended June 30, 2018 and 2017 , respectively. The Company recorded $1,927 and $5,377 of amortization of market lease intangible assets and liabilities as an increase to rental revenue for the six months ended June 30, 2018 and 2017 , respectively. Assets Held for Sale In the normal course of business, the Company identifies non-strategic assets for sale. The Company separately classifies properties held for sale in its Consolidated Financial Statements. The Company had no assets classified as held for sale as of June 30, 2018 and one asset classified as held for sale as of December 31, 2017, which had a net asset value of $402 . The net asset value of the asset held for sale represents the value contained in real estate investments. Real estate investments to be disposed of are reported at the lower of carrying amount or estimated fair value, less costs to sell. Once an asset is classified as held for sale, depreciation and amortization expense is no longer recorded. Discontinued Operations The Company did not have discontinued operations for the three and six months ended June 30, 2018 . The Company’s discontinued operations for the three and six months ended June 30, 2017 were related to the assets assumed in the Company’s merger transaction in 2015 and simultaneously designated as held for sale.

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Quarterly Presentation The accompanying Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In management’s opinion, all adjustments (consisting of normal recurring accruals) considered necessary for fair presentation have been included. The 2018 operating results for the period presented are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . These Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Annual Report on Form 10-K for the year ended December 31, 2017 of the Company and the Operating Partnership. The Consolidated Balance Sheets at December 31, 2017 were derived from the audited Consolidated Financial Statements at that date. Reclassifications Certain prior year balances have been reclassified to conform with the current year presentation. During the fourth quarter of 2017, the Company adopted Accounting Standards Update, or ASU, No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, which requires restricted cash and cash equivalents to be included with cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the Consolidated Statements of Cash Flows. As a result of the adoption, net cash provided by operating activities changed by $19 , net cash used in investing activities changed by $26,523 , and net cash provided by financing activities changed by $880 , for the six months ended June 30, 2017 . Principles of Consolidation The Consolidated Financial Statements include the Company’s accounts and those of the Company’s subsidiaries which are wholly-owned or controlled by the Company, or entities which are variable interest entities, or VIEs, in which the Company is the primary beneficiary. The primary beneficiary is the party that absorbs a majority of the VIE’s anticipated losses and/or a majority of the expected returns. The Company has evaluated its investments for potential classification as variable interests by evaluating the sufficiency of each entity’s equity investment at risk to absorb losses. Entities which the Company does not control and are considered VIEs, but for which the Company is not the primary beneficiary, are accounted for under the equity method. All significant intercompany balances and transactions have been eliminated. The equity interests of other limited partners in the Company’s Operating Partnership are reflected as noncontrolling interests. See Note 11 for more information on the Company’s noncontrolling interests. Real Estate Investments Real Estate Acquisitions The Company evaluates its acquisitions of real estate, including equity interests in entities that predominantly hold real estate assets, to determine if the acquired assets meet the definition of a business and need to be accounted for as a business combination, or alternatively, should be accounted for as an asset acquisition. An integrated set of assets and activities acquired does not meet the definition of a business if either (i) substantially all the fair value of the gross assets acquired is concentrated in either a single identifiable asset or a group of similar identifiable assets, or (ii) the asset and activities acquired do not contain at least an input and a substantive process that together significantly contribute to the ability to create outputs. The Company expects that its acquisitions of real estate will continue to not meet the definition of a business. Acquisitions of real estate that do not meet the definition of a business, including sale-leaseback transactions that have newly-originated leases and real estate investments under construction, or build-to-suit investments, are recorded as asset acquisitions. The accounting for asset acquisitions is similar to the accounting for business combinations, except that the acquisition consideration, including acquisition costs, is allocated to the individual assets acquired and liabilities assumed on a relative fair value basis. Based on this allocation methodology, asset acquisitions do not result in the recognition of goodwill or a bargain purchase. The Company incurs internal transaction costs, which are direct, incremental internal costs related to acquisitions, that are recorded within general and administrative expense. Additionally, for build-to-suit investments in which the Company may engage a developer to construct a property or provide funds to a tenant to develop a property, the Company capitalizes the funds provided to the developer/tenant and real estate taxes, if applicable, during the construction period. To determine the fair value of assets acquired and liabilities assumed in an acquisition, which generally include land, building, improvements, and intangibles, such as the value of above- and below-market leases and origination costs associated with the in-place leases at the acquisition date, the Company utilizes various estimates, processes and information to determine the as-if-vacant property value. Estimates of value are made using customary methods, including data from appraisals, comparable sales, and discounted cash flow analyses. Estimates of future cash flows are based on a number of factors including the historical operating results, known trends, and market/economic conditions that may affect the property. The Company assesses the fair value of leases assumed at acquisition based upon estimated cash flow projections that utilize appropriate discount rates and available market information. Refer to the policy section "Intangible Assets and Liabilities" for more information on the Company’s accounting for intangibles. Depreciation is computed using the straight-line method over the shorter of the estimated useful life at acquisition of the capitalized item or 40 years for buildings, five to ten years for building equipment and fixtures, and the lesser of the useful life or the remaining lease term for tenant improvements and leasehold interests. Maintenance and repair expenditures are expensed as incurred. For transactions that qualify as business combinations, the Company recognizes the assets acquired and liabilities assumed at fair value, including the value of intangible assets and liabilities, and any excess or deficit of the consideration transferred relative to the fair value of the net assets acquired is recorded as goodwill or a bargain purchase gain, as appropriate. Acquisition costs of business combinations are expensed as incurred. Capital Improvements In leasing space, the Company may provide funding to the lessee through a tenant allowance. Certain improvements are capitalized when they are determined to increase the useful life of the building. During construction of qualifying projects, the Company capitalizes project management fees as permitted to be charged under the lease, if incremental and identifiable. In accounting for tenant allowances, the Company determines whether the allowance represents funding for the construction of leasehold improvements and evaluates the ownership of such improvements. If the Company is considered the owner of the leasehold improvements, the Company capitalizes the amount of the tenant allowance and depreciates it over the shorter of the useful life of the leasehold improvements or the lease term. If the tenant allowance represents a payment for a purpose other than funding leasehold improvements, or in the event the Company is not considered the owner of the improvements for accounting purposes, the allowance is considered to be a lease incentive and is recognized over the lease term as a reduction of rental revenue. Impairments and Disposals The Company reviews the recoverability of a property’s carrying value when circumstances indicate a possible impairment of the value of a property, such as an adverse change in future expected occupancy or a significant decrease in the market price of an asset. The review of recoverability is based on an estimate of the future undiscounted cash flows, excluding interest charges, expected to result from the property’s use and eventual disposition. These estimates consider factors such as changes in strategy resulting in an increased or decreased holding period, expected future operating income, market and other applicable trends and residual value, as well as the effects of leasing demand, competition and other factors. If management determines impairment exists due to the inability to recover the carrying value of a property, for properties to be held and used, an impairment loss is recorded to the extent that the carrying value exceeds the estimated fair value of the property, and for assets held for sale, an impairment loss is recorded to the extent that the carrying value exceeds the fair value less the estimated cost of disposal. These assessments are recorded as an impairment loss in the Consolidated Statements of Operations in the period the determination is made. The estimated fair value of the asset becomes its new cost basis. For a depreciable long-lived asset to be held and used, the new cost basis will be depreciated or amortized over the remaining useful life of that asset. The Company recognizes sales of real estate properties upon closing, at which time the Company transfers control of the assets to the purchaser. Payments received from purchasers prior to closing are recorded as deposits. Profit on real estate sold is based on the transaction price and is recognized using the full accrual method upon closing. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents. The Company's restricted cash primarily consists of reserves for certain capital improvements, leasing, interest and real estate tax and insurance payments as required by certain mortgage note obligations, as well as proceeds from property sales held by qualified intermediaries to be used for tax-deferred, like-kind exchanges under section 1031 of the Internal Revenue Code of 1986, as amended, or the Internal Revenue Code. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sums to the total of the same such amounts shown in the Consolidated Statements of Cash Flows. As of June 30, 2018 2017 Cash and cash equivalents $ 59,741 $ 163,509 Restricted cash 12,026 40,326 Total cash, cash equivalents, and restricted cash $ 71,767 $ 203,835 Variable Interest Entities The Company had five consolidated VIEs and two unconsolidated VIEs as of June 30, 2018 and December 31, 2017 , which were determined based on the structure and control provisions of each entity. The Company’s five consolidated VIEs as of June 30, 2018 and December 31, 2017 included the Operating Partnership and four land parcels in Fort Mill, South Carolina acquired by an investment entity formed in December 2017, on which it will fund the development of four industrial facilities, or the Lakemont Development Investment. The Company has a 95.0% interest in the Lakemont Development Investment and will acquire the seller’s retained 5.0% interest when the properties are developed and leased. As of June 30, 2018 and December 31, 2017 , the Company’s carrying value of the Lakemont Development Investment was $4,765 and $4,584 , respectively. The Company’s two unconsolidated VIEs as of June 30, 2018 and December 31, 2017 included its retained non-investment grade subordinate bonds, preferred shares and ordinary shares of two collateralized debt obligations, or CDOs, which are collectively herein referred to as the Retained CDO Bonds. Refer to the “Other Assets” section of this Note 2 and also to Note 7 for more information on the accounting and valuation of the Retained CDO Bonds. As of June 30, 2018 and December 31, 2017 , the Company’s carrying value of the Retained CDO Bonds was $6,792 and $5,527 , respectively. Tenant and Other Receivables Tenant and other receivables are derived from rental revenue, tenant reimbursements, and management fees. Rental revenue is recorded on a straight-line basis over the initial term of the lease. Since many leases provide for rental increases at specified intervals, straight-line basis accounting requires the Company to record a receivable, and include in revenues, unbilled rent receivables that will only be received if the tenant makes all rent payments required through the expiration of the initial term of the lease. Tenant and other receivables also include receivables related to tenant reimbursements for common area maintenance expenses and certain other recoverable expenses that are recognized as revenue in the period in which the related expenses are incurred. Tenant and other receivables are recorded net of the allowance for doubtful accounts, which as of June 30, 2018 and December 31, 2017 was $692 and $638 , respectively. The Company continually reviews receivables related to rent, tenant reimbursements, and management fees, including incentive fees, and determines collectability by taking into consideration the tenant or asset management clients’ payment history, the financial condition of the tenant or asset management client, business conditions in the industry in which the tenant or asset management client operates and economic conditions in the area in which the property or asset management client is located. In the event that the collectability of a receivable is in doubt, the Company increases the allowance for doubtful accounts or records a direct write-off of the receivable, as appropriate. Intangible Assets and Liabilities As discussed above in policy section, "Real Estate Acquisitions," the Company follows the acquisition method of accounting for its asset acquisitions and business combinations and thus allocates the purchase price of acquired properties to tangible and identifiable intangible assets acquired based on their respective fair values. Identifiable intangible assets include amounts allocated to acquired leases for above- and below-market lease rates and the value of in-place leases. Management also considers information obtained about each property as a result of its pre-acquisition due diligence. Above-market and below-market lease values for properties acquired are recorded based on the present value of the difference between the contractual amount to be paid pursuant to each in-place lease and management’s estimate of the fair market lease rate for each such in-place lease, measured over a period equal to the remaining non-cancelable term of the lease. The present value calculation utilizes a discount rate that reflects the risks associated with the leases acquired. The above-market and below-market lease values are amortized as a reduction of and increase to rental revenue, respectively, over the remaining non-cancelable terms of the respective leases. If a tenant terminates its lease prior to its contractual expiration and no future rental payments will be received, any unamortized balance of the market lease intangibles will be written off to rental revenue. The aggregate value of in-place leases represents the costs of leasing costs, other tenant related costs, and lost revenue that the Company did not have to incur by acquiring a property that is already occupied. Factors considered by management in its analysis of the in-place lease intangibles include an estimate of carrying costs during the expected lease-up period for each property taking into account current market conditions and costs to execute similar leases. In estimating carrying costs, management includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the anticipated lease-up period. Management also estimates costs to execute similar leases including leasing commissions and other related expenses. The value of in-place leases is amortized to depreciation and amortization expense over the remaining non-cancelable term of the respective leases. In no event does the amortization period for intangible assets exceed the remaining depreciable life of the building. If a tenant terminates its lease prior to its contractual expiration and no future rental payments will be received, any unamortized balance of the in-place lease intangible will be written off to depreciation and amortization expense. Above-market and below-market ground rent intangibles are recorded for properties acquired in which the Company is the lessee pursuant to a ground lease assumed at acquisition. The above-market and below-market ground rent intangibles are valued similarly to above-market and below-market leases, except that, because the Company is the lessee as opposed to the lessor, the above-market and below-market ground lease values are amortized as a reduction of and increase to rent expense, respectively, over the remaining non-cancelable terms of the respective leases. Refer to Note 3 for further information on the Company’s intangible assets and liabilities. Revenue Adoption of ASC Topic 606, "Revenue from Contracts with Customers" The Company adopted ASC Topic 606, which is described below in the section “Recently Issued Accounting Pronouncements,” on January 1, 2018 using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under the new guidance, while prior period amounts are not adjusted and continue to be reported in accordance with the historic accounting guidance in ASC Topic 605. As a result of adoption, the Company recorded an increase to its opening retained earnings balance of $663 as of January 1, 2018, which represents the cumulative impact of the new guidance and is related to the Company’s sale of real estate to Strategic Office Partners in 2016. There was no impact to revenues recorded for the three and six months ended June 30, 2018 as a result of adoption of the new revenue guidance. Revenue Recognition The Company recognizes revenue when control of the promised goods or services is transferred to a customer, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company’s primary sources of revenue include rental revenue, operating expense reimbursements, third-party management fees, and other income, which are disaggregated on the Consolidated Statements of Operations and are described in detail below. Real Estate Investments Rental revenue from leases on real estate investments is recognized on a straight-line basis over the term of the lease, regardless of when payments are contractually due. For leases on properties that are under construction at the time of acquisition, the Company begins recognition of rental revenue upon completion of construction of the leased asset and delivery of the leased asset to the tenant. The Company’s lease agreements with tenants also generally contain provisions that require tenants to reimburse the Company for real estate taxes, insurance costs, common area maintenance costs, and other property-related expenses. Under lease arrangements in which the Company is the primary obligor for these expenses, the Company recognizes such amounts as both revenues and operating expenses. Under lease arrangements in which the tenant pays these expenses directly, such amounts are not included in revenues or expenses. These reimbursement amounts are recognized in the period in which the related expenses are incurred. Management Fees The Company’s asset and property management agreements may contain provisions for fees related to dispositions, administration of the assets including fees related to accounting, valuation and legal services, and management of capital improvements or projects on the underlying assets. The Company recognizes revenue for fees pursuant to its management agreements in the period in which they are earned. Deferred revenue from management fees received prior to the date earned are included in other liabilities on the Consolidated Balance Sheets. For management fee agreements that include multiple performance obligations, the Company allocates revenue to each performance obligation based on its relative standalone selling price, which is primarily determined based on the prices charged to customers. Certain of the Company’s asset management contracts and agreements with its unconsolidated equity investments include provisions that allow it to earn additional fees, generally described as incentive fees or promoted interests, based on the achievement of a targeted valuation or the achievement of a certain internal rate of return on the managed assets held by third parties or the equity investment. The Company’s incentive fees are accounted for as variable consideration and revenue is recognized for them based on the Company’s estimate of the expected amount to which it will be entitled in exchange for its services. The Company recognizes promoted interest in the period in which it is determined to be appropriately earned pursuant to the terms of the specific agreement. The values of incentive fees and promoted interest fees are periodically evaluated by management. Other Income Other income primarily consists of income accretion on the Company’s Retained CDO Bonds, realized foreign currency exchange gains (losses), and interest income. Foreign Currency The Company's European management platform performs asset and property management services in Europe. The Company has unconsolidated equity investments in Europe and Asia and previously had two wholly-owned properties in Canada until their dispositions in March 2017. The Company also has borrowings outstanding in euros and British pounds sterling under the multicurrency portion of its revolving credit facility. Refer to Note 4 for more information on the Company’s foreign unconsolidated equity investments. Other Assets The Company includes prepaid expenses, capitalized software costs, contract intangible assets, deferred costs, loan investments, goodwill, derivative assets, and Retained CDO Bonds in other assets. Loan Investments The Company may originate loans related to specific real estate development projects. In October 2017, the Company entered into an agreement to provide a mezzanine construction loan facility with a maximum commitment of $250,000 to an industrial developer as borrower. As of June 30, 2018 and December 31, 2017, the carrying value of the Company’s loan investments was $33,169 and $22,154 , respectively, which represents the cost, net of accumulated amortization of loan costs. A s of June 30, 2018 , the loan investments had a weighted average interest rate of 11.36% . The Company evaluates its loan investments for possible credit losses each period. There were no loan reserves recorded during the three and six months ended June 30, 2018 and all of the Company’s loan investments were performing in accordance with the terms of the relevant investments as of June 30, 2018 . Goodwill The Company recognized goodwill of $3,802 related to the acquisition of Gramercy Europe Limited in December 2014, which it adjusts each reporting period for the effect of foreign currency translation adjustments and tests for impairment on an annual basis, or more frequently if events or changes in circumstances indicate that the asset might be impaired. Based on the prevailing operating results and projected outlook for Gramercy Europe Limited as of June 30, 2018 , the Company determined the fair value of Gramercy Europe Limited was less than its carrying value and thus recorded an impairment loss of $3,293 on its goodwill during the three and six months ended June 30, 2018 . The fair value of Gramercy Europe Limited was determined using the income approach, wherein projections of discounted cash flows were based on factors such as forecasts of future real estate investments, operating results, management fees, and discount, promote hurdle and capitalization rates. The carrying value of goodwill at June 30, 2018 and December 31, 2017 was $0 and $3,272 , respectively. Retained CDO Bonds The Retained CDO Bonds are non-investment grade subordinate bonds, preferred shares and ordinary shares of two CDOs. Management estimated the timing and amount of cash flows expected to be collected and recognized an investment in the Retained CDO Bonds equal to the net present value of these discounted cash flows. There is no guarantee that the Company will realize any proceeds from this investment, or what the timing will be for the expected remaining life of the Retained CDO Bonds. The Company considers these investments to be not of high credit quality and does not expect a full recovery of interest and principal. Therefore, the Company has suspended interest income accruals on these investments. The Company classifies the Retained CDO Bonds as available for sale. On a quarterly basis, the Company evaluates the Retained CDO Bonds to determine whether significant changes in estimated cash flows or unrealized losses on these investments, if any, reflect a decline in value which is other-than-temporary. If there is a decrease in estimated cash flows and the investment is in an unrealized loss position, the Company will record an other-than-temporary impairment, or OTTI, in the Consolidated Statements of Operations. To determine the component of the OTTI related to expected credit losses, the Company compares the amortized cost basis of the Retained CDO Bonds to the present value of the revised expected cash flows, discounted using the pre-impairment effective yield. Conversely, if the security is in an unrealized gain position and there is a decrease or significant increase in expected cash flows, the Company will prospectively adjust the yield using the effective yield method. Refer to Note 7 for further discussion regarding the fair value measurement of the Retained CDO Bonds. For the three and six months ended June 30, 2018 , the Company did no t recognize any OTTI on its Retained CDO Bonds. For the three months ended June 30, 2017, the Company did no t recognize any OTTI on its Retained CDO Bonds and for the six months ended June 30, 2017, the Company recognized OTTI of $4,890 on its Retained CDO Bonds. A summary of the Company’s Retained CDO Bonds as of June 30, 2018 is as follows: Number of Securities Face Value Amortized Cost Gross Unrealized Gain Other-Than-Temporary Impairment Fair Value Weighted Average Expected Life (years) 6 $ 332,360 $ 5,756 $ 1,036 $ — $ 6,792 0.8 Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash investments, debt investments and accounts receivable. The Company places its cash investments in excess of insured amounts with high quality financial institutions. Concentrations of credit risk also arise when a number of the Company’s tenants or asset management clients are engaged in similar business activities or are subject to similar economic risks or conditions that could cause their inability to meet contractual obligations to the Company. The Company regularly monitors its portfolio to assess potential concentrations of credit risk. Management believes the current credit risk portfolio is reasonably well diversified. During the three and six months ended June 30, 2018 , there were no tenants that accounted for 10.0% or more of the Company's rental revenue. Additionally, during the three and six months ended June 30, 2018 , there were two states, Illinois and Texas , that each accounted for 10.0% or more of the Company’s rental revenue. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Recently Issued Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09 (Topic 606), Revenue from Contracts with Customers, which is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to customers in an amount reflecting the consideration it expects to receive in exchange for those goods or services. In April 2016 and February 2017, the FASB issued ASU 2016-10 and ASU 2017-05, respectively, which further clarified the new revenue recognition guidance under ASC Topic 606. The Company adopted the guidance on January 1, 2018 using the modified retrospective method, which did not have a material impact on its Consolidated Financial Statements. Refer to the “Revenue” section above for further detail. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities. The guidance requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and to record changes in instruments specific credit risk for financial liabilities measured under the fair value option in other comprehensive income. The update is effective for fiscal years beginning after December 15, 2017, and for interim periods therein. The Company adopted this standard in the first quarter of 2018 and the adoption did not have a material impact on its Consolidated Financial Statements. Refer to Note 8 for more information. I n February 2016, the FASB issued ASU 2016-02, Leases, which amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting. The update will be effective beginning in the first quarter of 2019 and early adoption is permitted. The new standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. The Company’s accounting for leases in which it is a lessor, which represents most of its leasing arrangements, will be largely unchanged under ASU 2016-02; however, the Company is a lessee in several operating and ground leases and the accounting for these arrangements is more significantly impacted by the new standard. Pursuant to the new guidance, lessees are required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. The Company is continuing to evaluate the impact of adopting the new leases standard on its Consolidated Financial Statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows Classification of Certain Cash Receipts and Cash Payments, which serves to reduce the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The update is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The Company adopted this standard in the first quarter of 2018 and the adoption did not have a material impact on its Consolidated Financial Statements. In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation: Scope of Modification Accounting. The amendment provides guidance on determining which changes to the terms and conditions of share-based payment awards require an entity to apply modification accounting. The guidance is effective for annual and interim periods beginning after December 15, 2017, with early adoption permitted under certain circumstances. The Company adopted this standard in the first quarter of 2018 and the adoption did not have a material impact on its Consolidated Financial Statements. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities. The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. The transition guidance provides companies with th

Unconsolidated Equity Investmen

Unconsolidated Equity Investments	6 Months Ended
	Jun. 30, 2018
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]
Unconsolidated Equity Investments	Unconsolidated Equity Investments The Company has investments in a variety of ventures. The Company will co-invest in entities that own multiple properties with various investors or with one partner. The Company may manage the ventures and earn fees, such as asset and property management fees, incentive fees, and promoted interest for its services, or one of the other partners will manage the ventures for similar such fees. Depending on the structure of the venture, the Company’s voting interest may be different than its economic interest. The Company accounts for substantially all of its unconsolidated equity investments under the equity method of accounting because it exercises significant influence, but does not unilaterally control the entities, and is not considered to be the primary beneficiary. In unconsolidated equity investments, the rights of the other investors are protective and participating. Unless the Company is determined to be the primary beneficiary, these rights preclude it from consolidating the investments. The investments are recorded initially at cost as unconsolidated equity investments, as applicable, and subsequently are adjusted for equity interest in net income and contributions and distributions. The amount of the investments on the Consolidated Balance Sheets is evaluated for impairment at each reporting period. None of the unconsolidated equity investment debt is recourse to the Company. Transactions with unconsolidated equity method entities are eliminated to the extent of the Company’s ownership in each such entity. Accordingly, the Company’s share of net income of these equity method entities is included in its consolidated net income. As of June 30, 2018 and December 31, 2017 , the Company owned properties through unconsolidated equity investments and had investment interests in these unconsolidated entities as follows: As of June 30, 2018 As of December 31, 2017 Investment Ownership % Voting Interest % Partner Investment in Unconsolidated Equity Investment 1 No. of Properties Investment in Unconsolidated Equity Investment 1 No. of Properties Strategic Office Partners 25.0% 25.0% TPG Real Estate $ 31,512 14 $ 28,243 13 E-Commerce JV 51.0% 50.0% Ample Glow Investments 70,475 4 17,798 — Gramercy European Property Fund III 19.9% 50.0% Various 27,045 13 2,949 — Goodman UK JV 80.0% 50.0% Goodman Group 13,480 1 15,768 1 Other 2 5.1% - 50.0% 5.1% - 50.0% Various 4,770 2 5,456 3 Total $ 147,282 34 $ 70,214 17 1. The amounts presented include a basis difference of $431 and $1,943 , net of accumulated amortization, for the Goodman UK JV as of June 30, 2018 and December 31, 2017 , respectively. The amounts presented include a basis difference of $(8,100) , net of accumulated amortization, for the E-Commerce JV as of June 30, 2018 . 2. As of June 30, 2018 , includes CBRE Strategic Partners Asia and the Morristown JV. As of December 31, 2017 , includes CBRE Strategic Partners Asia, the Philips JV, and the Morristown JV. The following is a summary of the Company’s unconsolidated equity investments for the six months ended June 30, 2018 : Unconsolidated Equity Investments Balance at January 1, 2018 $ 70,214 Contributions to unconsolidated equity investments 81,356 Equity in net loss of unconsolidated equity investments, including adjustments for basis differences (2,764 ) Other comprehensive loss of unconsolidated equity investments (1,632 ) Distributions from unconsolidated equity investments (555 ) Cumulative effect of accounting change 663 Balance at June 30, 2018 $ 147,282 Strategic Office Partners In August 2016, the Company partnered with TPG Real Estate, or TPG, to form Strategic Office Partners, an unconsolidated equity investment created for the purpose of acquiring, owning, operating, leasing and selling single-tenant office properties located in high-growth metropolitan areas in the United States. The Company provides asset and property management, accounting, construction, and leasing services to Strategic Office Partners, for which it earns management fees and is entitled to a promoted interest. TPG and the Company committed an aggregate $400,000 to Strategic Office Partners, including $100,000 from the Company. During the three and six months ended June 30, 2018 , the Company contributed $2,950 to Strategic Office Partners. As of June 30, 2018 , the Company contributed an aggregate of $32,427 to Strategic Office Partners. During the three and six months ended June 30, 2018 , the Company did not receive any distributions from Strategic Office Partners. In July 2018, the Company sold its 25.0% interest in Strategic Office Partners to TPG, and following the sale the Company’s has no outstanding commitment to Strategic Office Partners. Refer to Note 15 for more information on the transaction. E-Commerce JV In November 2017, the Company formed a joint venture with an investment partner, which will acquire, own and manage Class A distribution centers leased to leading e-commerce tenants on long-term leases across the United States, or the E-Commerce JV. The Company has joint control over the E-Commerce JV, which is shared equally with its investment partner. The Company provides asset and property management and accounting services to the E-Commerce JV, for which it earns management fees. The Company has committed capital to fund the E-Commerce JV’s initial acquisition of six properties, as well as the acquisition of additional properties in the future, subject to the partners' approval. The Company's pro rata funding commitment for the initial six properties is estimated at approximately $110,000 , of which approximately $80,000 will be funded in OP Units issued to the seller of the property and approximately $30,000 will be funded in cash. During the three and six months ended June 30, 2018 , the E-Commerce JV acquired two and four properties, respectively. During the three and six months ended June 30, 2018 , the Company contributed $14,435 and $15,565 , respectively, in cash and also contributed OP Units valued at approximately $12,416 and $37,557 , respectively, to the E-Commerce JV. European Investment Funds Gramercy European Property Fund III In October 2017, the Company formed a new European investment fund with several other equity investment partners, or the Gramercy European Property Fund III, which has total initial capital commitments of $310,643 ( €262,622 ) from all investors, of which the Company’s initial capital commitment is $61,730 ( €52,187 ), representing an interest of approximately 19.9% . The Company provides asset and property management and accounting services to the Gramercy European Property Fund III, for which it is entitled to management fees and a promoted interest. During the three and six months ended June 30, 2018 , the Gramercy European Property Fund III acquired eleven and thirteen properties, respectively. During the three and six months ended June 30, 2018 , the Company contributed $22,710 ( €18,987 ) and $25,170 ( €20,964 ), respectively, to the Gramercy European Property Fund III. As of June 30, 2018 , the Company contributed an aggregate of $28,186 ( €23,478 ) to the Gramercy European Property Fund III. Gramercy European Property Fund In July 2017, the Gramercy European Property Fund sold 100.0% of its assets to a third party, and, concurrently, the Company sold its 5.1% direct interest in the Goodman Europe JV to the same entity that acquired the Gramercy European Property Fund's assets. In connection with the sale transactions, the Company's management contract arrangement with the Gramercy European Property Fund was terminated; however, the Company continued to manage the assets for the new owner through July 4, 2018. Goodman UK JV The Goodman UK JV owns one industrial property in the United Kingdom. During the three and six months ended June 30, 2018 and 2017, the Company received no distributions from the Goodman UK JV. The following are the balance sheets for the Company’s unconsolidated equity investments at June 30, 2018 : Strategic Office Partners E-Commerce JV Gramercy European Property Fund III Goodman UK JV Other 1 Assets: Real estate assets, net 2 $ 277,863 $ 302,636 $ 314,022 $ 16,122 $ 60,361 Other assets 88,048 62,200 68,677 921 15,628 Total assets $ 365,911 $ 364,836 $ 382,699 $ 17,043 $ 75,989 Liabilities and members' equity: Mortgage notes payable $ 226,427 $ 216,863 $ 238,339 $ — $ — Other liabilities 14,009 9,786 8,253 — 15,793 Total liabilities 240,436 226,649 246,592 — 15,793 Company's equity 31,512 70,475 27,045 13,480 4,770 Other members' equity 93,963 67,712 109,062 3,563 55,426 Liabilities and members' equity $ 365,911 $ 364,836 $ 382,699 $ 17,043 $ 75,989 1. Includes CBRE Strategic Partners Asia and the Morristown JV. 2. Includes basis adjustments recorded by the Company to adjust the unconsolidated equity investments to fair value. The following are the balance sheets for the Company’s unconsolidated equity investments at December 31, 2017 : Strategic Office Partners E-Commerce JV Goodman UK JV Other 1 Assets: Real estate assets, net 2 $ 265,014 $ — $ 18,633 $ 107,949 Other assets 78,243 35,727 1,473 34,022 Total assets $ 343,257 $ 35,727 $ 20,106 $ 141,971 Liabilities and members' equity: Mortgage notes payable $ 213,205 $ — $ — $ 38,662 Other liabilities 15,002 830 203 19,329 Total liabilities 228,207 830 203 57,991 Company's equity 28,243 17,798 15,768 8,405 Other members' equity 86,807 17,099 4,135 75,575 Liabilities and members' equity $ 343,257 $ 35,727 $ 20,106 $ 141,971 1. Includes CBRE Strategic Partners Asia, the Philips JV, the Morristown JV, and the Gramercy European Property Fund III. 2. Includes basis adjustments recorded by the Company to adjust the unconsolidated equity investments to fair value. The following is a summary of the outstanding financing arrangements of the Company’s unconsolidated equity investments as of June 30, 2018 : Outstanding Balance 2 Property Unconsolidated Equity Investment Economic Ownership Interest Rate 1 Maturity Date June 30, 2018 December 31, 2017 Gramercy European Property Fund III Bridge Facility 3 Gramercy European Property Fund III 19.9% 1.50% 9/26/2019 $ 49,715 $ — Strategic Office Partners Facility 1 4 Strategic Office Partners 25.0% 5.02% 10/7/2019 169,380 169,380 Strategic Office Partners Facility 2 4 Strategic Office Partners 25.0% 6.03% 10/8/2020 52,020 39,540 E-Commerce JV Facility 4 E-Commerce JV 51.0% 3.38% 2/10/2023 220,000 — Gramercy European Property Fund III Facility 1 4 Gramercy European Property Fund III 19.9% 1.54% 3/12/2023 45,685 — Solingen, Germany Gramercy European Property Fund III 19.9% 1.66% 3/31/2023 9,785 — Gramercy European Property Fund III Facility 2 4 Gramercy European Property Fund III 19.9% 1.18% 6/22/2023 126,538 — Offenau, Germany Gramercy European Property Fund III 19.9% 1.89% 6/30/2023 9,125 — Henderson, NV Strategic Office Partners 25.0% 4.75% 8/6/2025 8,551 8,636 Total mortgage notes payable $ 690,799 $ 217,556 Net deferred financing costs and net debt discount (9,170 ) (4,351 ) Total mortgage notes payable, net $ 681,629 $ 213,205 1. Represents the current effective rate as of June 30, 2018 , including the swapped interest rate for mortgage notes that have interest rate swaps. The current interest rate is not adjusted to include the amortization of fair market value premiums or discounts. 2. Mortgage notes are presented at 100.0% of the amount held by the unconsolidated equity investment. 3. Represents the loan facility that is used to generate bridge financing for acquisitions and working capital needs of the Gramercy European Property Fund III. 4. As of June 30, 2018 , there were ten properties under the Strategic Office Partners Facility 1, three properties under the Strategic Office Partners Facility 2, four properties under the E-Commerce JV Facility, four properties under the Gramercy European Property Fund III Facility 1, and seven properties under the Gramercy European Property Fund III Facility 2. The following are the statements of operations for the Company’s unconsolidated equity investments for the three months ended June 30, 2018 : Strategic Office Partners E-Commerce JV Gramercy European Property Fund III Goodman UK JV Other 1 Revenues $ 11,765 $ 6,771 $ 1,730 $ 180 $ (5,632 ) Operating expenses 4,328 1,703 376 105 272 Interest expense 3,390 2,003 450 — — Depreciation and amortization 5,148 2,855 761 210 20 Total expenses 12,866 6,561 1,587 315 292 Net income (loss) from operations (1,101 ) 210 143 (135 ) (5,924 ) Gain (loss) on derivatives 177 — (781 ) — — Loss on extinguishment of debt — — (461 ) — — Provision for taxes — — (36 ) — — Net income (loss) $ (924 ) $ 210 $ (1,135 ) $ (135 ) $ (5,924 ) Company's share in net income (loss) $ (92 ) $ 260 $ (184 ) $ (108 ) $ (312 ) Adjustments for REIT basis 2 — 63 — (1,465 ) — Company's equity in net income (loss) within continuing operations $ (92 ) $ 323 $ (184 ) $ (1,573 ) $ (312 ) 1. Includes CBRE Strategic Partners Asia and the Morristown JV. 2. Goodman UK JV amount includes write-down of $1,462 recorded on the Company’s outside basis during the three months ended June 30, 2018 related to its accumulated foreign currency translation adjustments recorded on the investment. The following are statements of operations for the Company’s unconsolidated equity investments for the six months ended June 30, 2018 : Strategic Office Partners E-Commerce JV Gramercy European Property Fund III Goodman UK JV Other 1 Revenues $ 22,908 $ 8,936 $ 2,212 $ 180 $ (3,638 ) Operating expenses 8,479 2,286 1,058 365 378 Interest expense 6,503 2,672 547 — 666 Depreciation and amortization 9,971 3,717 970 416 353 Total expenses 24,953 8,675 2,575 781 1,397 Net income (loss) from operations (2,045 ) 261 (363 ) (601 ) (5,035 ) Gain (loss) on derivatives 669 — (781 ) — — Loss on extinguishment of debt — (1,200 ) (461 ) — — Provision for taxes — — (36 ) — — Net loss $ (1,376 ) $ (939 ) $ (1,641 ) $ (601 ) $ (5,035 ) Company’s share in net loss $ (66 ) $ (260 ) $ (277 ) $ (481 ) $ (292 ) Adjustments for REIT basis 2 — 81 — (1,469 ) — Company’s equity in net loss within continuing operations $ (66 ) $ (179 ) $ (277 ) $ (1,950 ) $ (292 ) 1. Includes CBRE Strategic Partners Asia and the Morristown JV. 2. Goodman UK JV amount includes write-down of $1,462 recorded on the Company’s outside basis during the six months ended June 30, 2018 related to its accumulated foreign currency translation adjustments recorded on the investment. The following are the statements of operations for the Company’s unconsolidated equity investments for the three months ended June 30, 2017 : Gramercy European Property Fund 1 Goodman Europe JV Gramercy European Property Fund 2 Total Strategic Office Partners Goodman UK JV Other 3 Revenues $ 5,323 $ 11,479 $ 16,802 $ 7,174 $ 293 $ 1,324 Operating expenses 945 2,802 3,747 2,316 225 399 Interest expense 614 1,798 2,412 2,055 — 700 Depreciation and amortization 2,024 5,322 7,346 2,852 261 333 Total expenses 3,583 9,922 13,505 7,223 486 1,432 Net income (loss) from operations 1,740 1,557 3,297 (49 ) (193 ) (108 ) Gain (loss) on derivatives — 1,049 1,049 (413 ) — — Provision for taxes (15 ) (424 ) (439 ) — (20 ) — Net income (loss) $ 1,725 $ 2,182 $ 3,907 $ (462 ) $ (213 ) $ (108 ) Company’s share in net income (loss) $ 88 $ 439 $ 527 $ (36 ) $ (171 ) $ 5 Adjustments for REIT basis 2 (37 ) — (37 ) — (40 ) — Company’s equity in net income (loss) within continuing operations $ 51 $ 439 $ 490 $ (36 ) $ (211 ) $ 5 1. As of and for the three months ended June 30, 2017 , the Company had a 5.1% direct interest in the Goodman Europe JV as well as an indirect interest in the remaining 94.9% interest that was held through the Company’s 14.2% interest in the Gramercy European Property Fund. For the three months ended June 30, 2017 , the Company’s equity in net income (loss) from the entities is based on these ownership interest percentages during the period. 2. Excludes the results of the Gramercy European Property Fund’s 94.9% interest in the Goodman Europe JV, as the Goodman Europe JV is separately presented. 3. Includes CBRE Strategic Partners Asia, the Philips JV, the Morristown JV, and European Fund Carry Co. The following are the statements of operations for the Company’s unconsolidated equity investments for the six months ended June 30, 2017 : Gramercy European Property Fund 1 Goodman Europe JV Gramercy European Property Fund 2 Total Strategic Office Partners Goodman UK JV Other 3 Revenues $ 10,278 $ 21,597 $ 31,875 $ 12,700 $ 588 $ (7 ) Operating expenses 1,867 5,753 7,620 3,790 527 975 Interest expense 1,286 3,272 4,558 3,565 — 1,341 Depreciation and amortization 4,045 9,795 13,840 5,355 636 666 Total expenses 7,198 18,820 26,018 12,710 1,163 2,982 Net income (loss) from operations 3,080 2,777 5,857 (10 ) (575 ) (2,989 ) Gain (loss) on derivatives — 2,270 2,270 (762 ) — — Provision for taxes (32 ) (278 ) (310 ) — (28 ) — Net income (loss) $ 3,048 $ 4,769 $ 7,817 $ (772 ) $ (603 ) $ (2,989 ) Company’s share in net income (loss) $ 155 $ 885 $ 1,040 $ (51 ) $ (483 ) $ (150 ) Adjustments for REIT basis 2 (73 ) — (73 ) — (129 ) — Company’s equity in net income (loss) within continuing operations $ 82 $ 885 $ 967 $ (51 ) $ (612 ) $ (150 ) 1. As of and for the six months ended June 30, 2017 , the Company had a 5.1% direct interest in the Goodman Europe JV as well as an indirect interest in the remaining 94.9% interest that was held through the Company’s 14.2% interest in the Gramercy European Property Fund. For the six months ended June 30, 2017 , the Company’s equity in net income (loss) from the entities is based on these ownership interest percentages during the period. 2. Excludes the results of the Gramercy European Property Fund’s 94.9% interest in the Goodman Europe JV, as the Goodman Europe JV is separately presented. 3. Includes CBRE Strategic Partners Asia, the Philips JV, the Morristown JV, and European Fund Carry Co.

Debt Obligations

Debt Obligations	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt Obligations	Debt Obligations Secured Debt Mortgage Notes Certain real estate assets are subject to mortgage notes. During the six months ended June 30, 2018 , the Company did not assume any mortgages notes. During the year ended December 31, 2017 , the Company assumed $181,107 of non-recourse mortgages in connection with seven real estate acquisitions. During the three and six months ended June 30, 2018, the Company paid off the mortgage notes on four properties and recorded a net gain on extinguishment of debt of $83 related to the payoffs. During the three and six months ended June 30, 2017, the Company paid off the mortgage notes on two properties. During the six months ended June 30, 2017, the Company refinanced the debt on two properties encumbered by a mortgage loan for $10,456 and subsequently transferred the mortgage on these two properties to the buyer of the properties. During the three and six months ended June 30, 2017, the Company recorded a net gain on the early extinguishment of debt of $268 and $60 , respectively. The Company’s mortgage notes include a series of financial and other covenants with which the Company must comply in order to borrow under them. The Company was in compliance with the covenants under the mortgage note facilities as of June 30, 2018 . The following is a summary of the Company’s secured financing arrangements as of June 30, 2018 and December 31, 2017 : Property Interest Rate 1 Maturity Date Outstanding Balance June 30, 2018 December 31, 2017 Philadelphia, PA 4.99% 1/1/2019 $ 11,743 $ 11,943 Bridgeview, IL 3.90% 5/1/2019 5,745 5,838 Spartanburg, SC 3.20% 6/1/2019 427 632 Charleston, SC 3.11% 8/1/2019 181 457 Lawrence, IN 5.02% 1/1/2020 19,730 20,061 Charlotte, NC 3.28% 1/1/2020 1,185 1,538 Hawthorne, CA 3.52% 8/1/2020 16,960 17,207 Charleston, SC 3.32% 10/1/2020 633 758 Charleston, SC 2.97% 10/1/2020 622 746 Charleston, SC 3.37% 10/1/2020 622 746 Charlotte, NC 3.38% 10/1/2020 540 647 Des Plaines, IL 5.54% 10/31/2020 2,344 2,385 Waco, TX 4.75% 12/19/2020 14,741 14,890 Deerfield, IL 3.71% 1/1/2021 10,263 10,447 Winston-Salem, NC 3.41% 6/1/2021 2,913 3,354 Winston-Salem, NC 3.42% 7/1/2021 971 1,114 Logistics Portfolio - Pool 1 2 4.27% 1/1/2022 37,603 38,107 CCC Portfolio 2 4.24% 10/6/2022 22,572 22,814 Logistics Portfolio - Pool 4 2 4.36% 12/5/2022 79,500 79,500 Romeoville, IL 3.80% 4/6/2023 24,724 24,951 Romeoville, IL 3 9.37% 4/6/2023 6,605 6,623 KIK USA Portfolio 2 4.31% 7/6/2023 7,001 7,154 Yuma, AZ 5.27% 12/6/2023 11,752 11,858 Allentown, PA 5.16% 1/6/2024 22,487 22,690 Spartanburg, SC 3.72% 2/1/2024 5,256 5,635 Natick, MA 5.21% 3/1/2024 31,027 31,224 Natick, MA 3 10.38% 3/1/2024 3,447 3,469 Maple Grove, MN 3.88% 5/6/2024 16,201 16,380 Curtis Bay, MD 4.31% 7/1/2024 13,500 13,500 Rialto, CA 3.91% 8/1/2024 54,344 54,741 Houston, TX 3.68% 9/1/2024 26,000 26,000 Durham, NC 4.02% 9/6/2024 3,597 3,631 Charleston, SC 3.80% 2/1/2025 5,658 6,001 Hackettstown, NJ 5.49% 3/6/2026 9,387 9,455 Hutchins, TX 5.41% 6/1/2029 20,955 21,578 Greenwood, IN 3.59% 6/15/2018 — 7,257 Greenfield, IN 3.63% 6/15/2018 — 5,865 Logistics Portfolio - Pool 3 3.96% 8/1/2018 — 43,302 Total mortgage notes payable $ 491,236 $ 554,498 Net deferred financing costs and net debt premium 7,979 9,023 Total mortgage notes payable, net $ 499,215 $ 563,521 1. Represents the interest rate as of June 30, 2018 that was recorded for financial reporting purposes, which reflects the effect of interest rate swaps and amortization of financing costs and fair market value premiums or discounts. 2. As of June 30, 2018 , there were three properties under the Logistics Portfolio - Pool 1 mortgage, five properties under the CCC Portfolio mortgage, six properties under the Logistics Portfolio - Pool 4 mortgage, and three properties under the KIK USA Portfolio mortgage. 3. Mortgage notes represent mezzanine financing at the properties. Unsecured Debt 2015 Credit Facility and Term Loans In December 2015, the Company entered into an agreement, or the Credit Agreement, for a new $1,900,000 credit facility, or the 2015 Credit Facility, consisting of an $850,000 senior unsecured revolving credit facility, or the 2015 Revolving Credit Facility, and a $1,050,000 term loan facility with JPMorgan Securities LLC and Merrill Lynch, Pierce, Fenner and Smith Incorporated. The 2015 Revolving Credit Facility consists of a $750,000 U.S. dollar revolving credit facility and a $100,000 multicurrency revolving credit facility. The 2015 Revolving Credit Facility matures in January 2020, but may be extended for two additional six-month periods upon the payment of applicable fees and satisfaction of certain customary conditions. The term loan facility, or the 2015 Term Loan, consists of a $300,000 term loan facility that matures in January 2019 with one 12-month extension option, or the 3-Year Term Loan, and a $750,000 term loan facility that matures in January 2021, or the 5-Year Term Loan. In December 2015, the Company also entered into a $175,000 7 -year unsecured term loan with Capital One, N.A, or the 7-Year Term Loan, which matures in January 2023 . In October 2017, the Company modified the 7-Year Term Loan by increasing the loan amount to $400,000 and reducing the interest rate to the terms described below. Outstanding borrowings under the 2015 Revolving Credit Facility incur interest at a floating rate based upon, at the Company's option, either (i) adjusted LIBOR plus an applicable margin ranging from 0.88% to 1.55% , depending on the Company's credit ratings, or (ii) the alternate base rate plus an applicable margin ranging from 0.00% to 0.55% , depending on the Company's credit ratings. The Company is also required to pay quarterly in arrears a 0.13% to 0.30% facility fee, depending on its credit ratings, on the total commitments under the 2015 Revolving Credit Facility. Outstanding borrowings under the 2015 Term Loan and the 7-Year Term Loan incur interest at a floating rate based upon, at the Company's option, either (i) adjusted LIBOR plus an applicable margin ranging from 0.90% to 1.75% , depending on the Company's credit ratings, or (ii) the alternate base rate plus an applicable margin ranging from 0.00% to 0.75% , depending on the Company's credit ratings. The alternate base rate for the 2015 Revolving Credit Facility and the 7-Year Term Loan is the greater of (x) the prime rate announced by JPMorgan Chase Bank, N.A. or Capital One, respectively, (y) 0.50% above the Federal Funds Effective Rate, and (z) the adjusted LIBOR for a one-month interest period plus 1.00% . The Company’s unsecured borrowing facilities include a series of financial and other covenants with which the Company must comply in order to borrow under the facilities. The Company was in compliance with the covenants under the facilities as of June 30, 2018 . Refer to the table at the end of this Note 5 for specific terms and the Company’s outstanding borrowings under the facilities. Senior Unsecured Notes During 2015 and 2016, the Company issued and sold an aggregate $500,000 principal amount of senior unsecured notes payable in private placements, which have maturities ranging from 2022 through 2026 and bear interest semiannually at rates ranging from 3.89% to 4.97% . Refer to the table later in Note 5 for specific terms of the Company's Senior Unsecured Notes. Exchangeable Senior Notes In September 2017, the Company's $115,000 of 3.75% Exchangeable Senior Notes were exchanged for 5,258,420 of the Company's common shares. The terms of the Company’s unsecured debt obligations and outstanding balances as of June 30, 2018 and December 31, 2017 are set forth in the table below: Stated Interest Rate Effective Interest Rate 1 Maturity Date Outstanding Balance June 30, 2018 December 31, 2017 2015 Revolving Credit Facility - USD tranche 3.08 % 3.08 % 1/8/2020 $ 405,000 $ 345,000 2015 Revolving Credit Facility - Multicurrency tranche 1.11 % 1.11 % 1/8/2020 36,773 12,162 3-Year Term Loan 3.23 % 2.33 % 1/8/2019 300,000 300,000 5-Year Term Loan 3.23 % 2.70 % 1/8/2021 750,000 750,000 7-Year Term Loan 3.08 % 3.00 % 1/9/2023 400,000 400,000 2015 Senior Unsecured Notes 4.97 % 5.07 % 12/17/2024 150,000 150,000 2016 Senior Unsecured Notes 3.89 % 4.00 % 12/15/2022 150,000 150,000 2016 Senior Unsecured Notes 4.26 % 4.38 % 12/15/2025 100,000 100,000 2016 Senior Unsecured Notes 4.32 % 4.43 % 12/15/2026 100,000 100,000 Total unsecured debt 2,391,773 2,307,162 Net deferred financing costs and net debt discount (4,680 ) (5,063 ) Total unsecured debt, net $ 2,387,093 $ 2,302,099 1. Represents the rate at which interest expense is recorded for financial reporting purposes as of June 30, 2018 , which reflects the effect of interest rate swaps and amortization of financing costs and fair market value premiums or discounts. Combined aggregate principal maturities of the Company’s unsecured debt obligations and non-recourse mortgages, in addition to associated interest payments, as of June 30, 2018 are as follows: July 1 to December 31, 2018 2019 2020 2021 2022 Thereafter Above market interest Total 2015 Revolving Credit Facility $ — $ — $ 441,773 $ — $ — $ — $ — $ 441,773 Term Loans — 300,000 — 750,000 — 400,000 — 1,450,000 Mortgage Notes Payable 1 6,880 30,450 62,834 19,256 141,929 229,887 — 491,236 Senior Unsecured Notes — — — — 150,000 350,000 — 500,000 Interest Payments 2 54,009 104,625 89,976 58,015 53,868 64,822 3,299 428,614 Total $ 60,889 $ 435,075 $ 594,583 $ 827,271 $ 345,797 $ 1,044,709 $ 3,299 $ 3,311,623 1. Mortgage note payments reflect accelerated repayment dates, when applicable, pursuant to the related agreement. 2. Interest payments do not reflect the effect of interest rate swaps.

Transactions with Trustee Relat

Transactions with Trustee Related Entities and Related Parties	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Transactions with Trustee Related Entities and Related Parties	Transactions with Trustee Related Entities and Related Parties The Company’s CEO, Gordon F. DuGan, was on the board of directors of the Gramercy European Property Fund prior to its sale in July 2017 and committed and fully funded approximately $1,388 ( €1,250 ) in capital to the Gramercy European Property Fund. The two Managing Directors of Gramercy Europe Limited collectively committed and fully funded approximately $1,388 ( €1,250 ) in capital to the Gramercy European Property Fund prior to the sale of its assets in July 2017.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements ASC 820-10, “Fair Value Measurements and Disclosures,” provides guidance on the fair value measurement of a financial asset or liability. Inputs used to develop fair value measurements are classified into one of three categories: Level I, defined as observable inputs such as quoted prices in active markets for identical assets or liabilities; Level II, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level III, defined as unobservable inputs for which there is little or no market or pricing data, thus requiring management to use its judgment and develop its own assumptions. The following table presents the carrying value in the financial statements and approximate fair value of assets and liabilities measured on a recurring and non-recurring basis at June 30, 2018 and December 31, 2017 : June 30, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value Financial assets: Interest rate swaps $ 35,212 $ 35,212 $ 19,668 $ 19,668 Retained CDO Bonds 6,792 6,792 5,527 5,527 Real estate investments 1 2,592 2,592 87,996 87,996 Investment in CBRE Strategic Partners Asia 2,062 2,062 2,820 2,820 Loan investments 2 33,169 28,872 22,154 21,362 Financial liabilities: Interest rate swaps $ — $ — $ 173 $ 173 Long-term debt: 2015 Revolving Credit Facility 2 441,773 441,823 357,162 357,369 3-Year Term Loan 2 300,000 300,066 300,000 300,091 5-Year Term Loan 2 750,000 750,573 750,000 750,678 7-Year Term Loan 2 398,330 400,006 398,152 400,010 Mortgage notes payable 2 499,215 502,870 563,521 573,826 Senior Unsecured Notes 2 496,990 494,455 496,785 513,229 1. Amounts represent two and seven real estate investments, respectively, that were impaired by the Company and held as of June 30, 2018 and December 31, 2017 . 2. Long-term debt instruments are classified as Level III due to the significance of unobservable inputs which are based upon management assumptions. The following methods and assumptions were used to estimate the fair value of each class of assets and liabilities for which it is practicable to estimate the value: Cash and cash equivalents, marketable securities, accrued interest, and accounts payable: These balances in the Consolidated Financial Statements reasonably approximate their fair values due to the items’ short maturities. Loan investments: Loan investments are presented in other assets on the Consolidated Financial Statements at amortized cost and not fair value. The fair value of each investment is estimated by a discounted cash flow model, using discount rates that best reflect current market rates for financings with similar characteristics and credit quality. Mortgage notes payable, unsecured term loans, unsecured revolving credit facilities and senior unsecured notes: These instruments are presented in the Consolidated Financial Statements at amortized cost and not at fair value. The fair value of each instrument is estimated by a discounted cash flows model, using discount rates that best reflect current market rates for financings with similar characteristics and credit quality. Retained CDO Bonds, investment in CBRE Strategic Partners Asia, real estate investments, and interest rate swaps: Refer to section below, “Valuation of Level III Instruments,” for valuation methods and assumptions used for these Level III assets and liabilities measured at fair value in the Consolidated Financial Statements. The following discussion of fair value was determined by the Company using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair value. Accordingly, fair values are not necessarily indicative of the amounts the Company could realize on disposition of the assets or liabilities. The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts. Assets and liabilities measured at fair value on a recurring and non-recurring basis are categorized as follows: At June 30, 2018 Total Level I Level II Level III Financial Assets: Retained CDO Bonds $ 6,792 $ — $ — $ 6,792 Real estate investments 2,592 — — 2,592 Investment in CBRE Strategic Partners Asia 2,062 — — 2,062 Interest rate swaps 35,212 — — 35,212 $ 46,658 $ — $ — $ 46,658 At December 31, 2017 Total Level I Level II Level III Financial Assets: Retained CDO Bonds $ 5,527 $ — $ — $ 5,527 Real estate investments 87,996 — — 87,996 Investment in CBRE Strategic Partners Asia 2,820 — — 2,820 Interest rate swaps 19,668 — — 19,668 $ 116,011 $ — $ — $ 116,011 Financial Liabilities: Interest rate swaps $ (173 ) $ — $ — $ (173 ) $ (173 ) $ — $ — $ (173 ) Valuation of Level III Instruments Retained CDO Bonds: Retained CDO Bonds are valued on a recurring basis using an internally developed discounted cash flow models, which require significant assumptions and judgment. The models are most sensitive to the unobservable inputs such as the amount of the recoveries of the underlying securities. Investment in CBRE Strategic Partners Asia: The Company's investment in CBRE Strategic Partners Asia is based on the Level III valuation inputs applied by the investment manager of CBRE Strategic Partners Asia, utilizing a mix of different approaches for valuing the underlying real estate related investments within the investment company. The valuations are most sensitive to the unobservable inputs of discount rates, as well as capitalization rates an expected future cash flows. Real estate investments: Real estate investments impaired during a period are reported at estimated fair value and real estate investments impaired during a period that are classified as held for sale as of the end of the period are reported at estimated fair value less costs to sell. The fair value of real estate investments and their related lease intangibles is determined using third-party valuation support, including purchase-sale contracts and other available market information. Key assumptions in the valuations, to which the fair value determinations are most sensitive, include discount and capitalization rates as well as expected future cash flows. Interest rate swaps: The Company's derivative instruments as of June 30, 2018 and December 31, 2017 consist of interest rate swaps, which are valued with the assistance of a third-party derivative specialist using a discounted cash flow model, that requires a combination of observable market-based inputs, such as interest rate curves, and unobservable inputs which require significant judgment such as the credit valuation adjustments due to the risk of nonperformance by both the Company and its counterparties. The most significant unobservable input in the fair valuation of interest rate swaps is the credit valuation adjustment as it requires significant management judgment regarding changes in the credit risk of the Company or its counterparties, however the primary driver of the fair value of the interest rate swaps is the forward interest rate curve. Fair Value on a Recurring Basis Quantitative information regarding the valuation techniques and the range of significant unobservable Level III inputs used to determine fair value measurements on a recurring basis as of June 30, 2018 are as follows: Financial Asset (Liability) Fair Value Valuation Technique Unobservable Inputs Range Non-investment grade, subordinate CDO bonds $ 6,792 Discounted cash flows Discount rate 19.0% Investment in CBRE Strategic Partners Asia 2,062 Discounted cash flows Discount rate 20.0% Interest rate swaps 35,212 Hypothetical derivative method Credit borrowing spread 110 to 175 basis points The following rollforward table reconciles the beginning and ending balances of financial assets (liabilities) measured at fair value on a recurring basis using Level III inputs as of June 30, 2018 : Retained CDO Bonds Investment in CBRE Strategic Partners Asia Interest Rate Swaps Total Financial Assets (Liabilities) - Level III Balance at January 1, 2018 $ 5,527 $ 2,820 $ 19,495 $ 27,842 Amortization of discounts or premiums 646 — (35 ) 611 Adjustments to fair value: Termination of derivative instrument — — (11,288 ) (11,288 ) Unrealized gain on derivatives — — 27,040 27,040 Unrealized loss in other comprehensive income from fair value adjustment 619 — — 619 Total loss on fair value adjustments — (251 ) — (251 ) Distributions from financial assets — (507 ) — (507 ) Balance at June 30, 2018 $ 6,792 $ 2,062 $ 35,212 $ 44,066 Fair Value on a Non-Recurring Basis The Company measures its real estate investments impaired during a period, including both assets classified as held for sale and assets held for investment, on a non-recurring basis, and records impairment on these assets as a result of a change in intent to hold the real estate investments. There were two assets measured on a non-recurring basis as of June 30, 2018 , which were both classified as held for investment and recorded at $2,592 as of June 30, 2018 . There were seven assets measured on a non-recurring basis as of December 31, 2017 , which were all classified as held for investment and recorded at $87,996 as of December 31, 2017 .

Derivatives and Non-Derivative

Derivatives and Non-Derivative Hedging Instruments	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Non-Derivative Hedging Instruments	Derivatives and Non-Derivative Hedging Instruments In the normal course of business, the Company is exposed to the effect of interest rate changes and foreign exchange rate changes. The Company limits these risks by following established risk management policies and procedures including the use of derivatives and net investment hedges. The Company uses a variety of derivative instruments to manage, or hedge, interest rate risk. The Company enters into hedging and derivative instruments that will be maximally effective in reducing the interest rate risk and foreign currency exchange rate risk exposure that they are designated to hedge. This effectiveness is essential for qualifying for hedge accounting. Instruments that meet these hedging criteria are formally designated as hedges at the inception of the derivative contract. The Company uses a variety of commonly used derivative products that are considered “plain vanilla” derivatives. These derivatives typically include interest rate swaps, forward starting swaps, caps, collars and floors. The Company expressly prohibits the use of unconventional derivative instruments and the use of derivative instruments for trading or speculative purposes. Further, the Company has a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors. The Company recognizes all derivatives on the Consolidated Balance Sheets at fair value within other assets or other liabilities, depending on the balance at the end of the period. Derivatives that are not designated as hedges must be adjusted to fair value through income. If a derivative is designated and qualifies as a hedge, depending on the nature of the hedge, changes in the fair value of the derivative will be recognized in other comprehensive income until the hedged item is recognized in earnings. Prior to the Company’s adoption of ASU 2017-12 on January 1, 2018, described in Note 2 , the ineffective portion of the change in fair value of a derivative designated as a hedge was immediately recognized in earnings, however subsequent to adoption, the entire change in fair value is recognized in other comprehensive income until the hedged item is recognized in earnings. As a result of adoption, the Company recorded a decrease to its opening retained earnings balance and a corresponding increase to its opening accumulated other comprehensive income balance of $ 103 as of January 1, 2018, which represents the cumulative amount of hedge ineffectiveness recorded in the Consolidated Statements of Operations at the time of adoption. Derivative accounting may increase or decrease reported net income and shareholders’ equity prospectively, depending on future levels of the LIBOR swap spreads and other variables affecting the fair values of derivative instruments and hedged items, but will have no effect on cash flows, provided the contract is carried through to full term. Refer to Note 7 for additional information on the Company's derivative instruments, including the fair value measurement of these instruments. Borrowings on the Company’s multicurrency tranche of the 2015 Revolving Credit Facility, which are designated as non-derivative net investment hedges, are recognized at par value based on the exchange rate in effect on the date of the draw. Subsequent changes in the exchange rates of the Company’s non-derivative net investment hedges are recognized as part of the cumulative foreign currency translation adjustment within other comprehensive income. The Company’s derivatives and hedging instruments as of June 30, 2018 are as follows: Benchmark Rate Notional Value Strike Rate Effective Date Expiration Date Fair Value Interest Rate Swap - Waco 1 mo. USD-LIBOR-BBA 14,741 USD 4.55% 12/19/2013 12/19/2020 $ 64 Interest Rate Swap - 3-Year Term Loan 1 mo. USD-LIBOR-BBA 100,000 USD 1.22% 12/19/2016 12/17/2018 472 Interest Rate Swap - 3-Year Term Loan 1 mo. USD-LIBOR-BBA 100,000 USD 1.23% 12/19/2016 12/17/2018 470 Interest Rate Swap - 3-Year Term Loan 1 mo. USD-LIBOR-BBA 100,000 USD 1.24% 12/19/2016 12/17/2018 465 Interest Rate Swap - 5-Year Term Loan 1 mo. USD-LIBOR-BBA 750,000 USD 1.60% 12/17/2015 12/17/2020 19,539 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 175,000 USD 1.82% 12/17/2015 1/9/2023 6,853 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 60,000 USD 1.95% 10/13/2017 1/9/2023 2,025 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 40,000 USD 2.01% 10/13/2017 1/9/2023 1,243 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 39,500 USD 1.96% 10/13/2017 1/9/2023 1,298 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 31,500 USD 1.96% 10/13/2017 1/9/2023 1,038 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 31,500 USD 2.00% 10/13/2017 1/9/2023 991 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 22,500 USD 1.95% 10/13/2017 1/9/2023 754 Net Investment Hedge in GBP-denominated investments USD-GBP exchange rate 9,000 GBP N/A 7/15/2016 N/A — Net Investment Hedge in EUR-denominated investments USD-EUR exchange rate 21,300 EUR N/A 3/8/2018 N/A — Total hedging instruments $ 35,212 As of June 30, 2018 , the Company’s derivative instruments consisted of interest rate swaps, which are cash flow hedges used to hedge exposure to variability in future interest payments on its debt facilities. The Company's interest rate swap derivative instruments were reported in other assets at fair value of $35,212 at June 30, 2018 . The table below details the location in the financial statements of the gain or loss recognized on the interest rate swaps designated as cash flow hedges for the three and six months ended June 30, 2018 and 2017 : Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Accumulated other comprehensive income: Gain recognized in accumulated other comprehensive income 1 $ 4,990 $ — $ 27,143 $ — Interest expense: Loss reclassified from accumulated other comprehensive income into interest expense 1 $ 271 $ 271 $ 539 $ 539 Gain recognized in interest expense (ineffective portion) 2 — — — 46 Total recognized in interest expense on statements of operations $ 271 $ 271 $ 539 $ 585 Gain on derivative instruments: Gain reclassified from other comprehensive income into gain on derivative instruments 3 $ 14,970 $ — $ 14,970 $ — 1. Periods prior to January 1, 2018, when the Company adopted ASU 2017-12, include only the effective portion and periods subsequent to January 1, 2018 include both the effective and ineffective portions as the two amounts are no longer separately measured and reported. The six months ended June 30, 2018 includes $103 related to the adoption of ASU 2017-02. 2. Represents the ineffective portion and pertains only to periods prior to January 1, 2018, when the Company adopted ASU 2017-12. 3. Amounts represent gain recognized during the three and six months ended June 30, 2018 related to the Company’s termination of its forward starting swap in June 2018. During the next 12 months, the Company expects that $(9,553) will be reclassified from other comprehensive income as an increase in interest expense for the Company’s interest rate swaps as of June 30, 2018 . Additionally, the Company will recognize $1,024 in interest expense on a straight-line basis over the remaining original term of terminated swaps through June 2019, representing amortization of the remaining accumulated other comprehensive income balance related to the swap. The Company hedges exposure to changes in the exchange rates underlying its investments based in foreign currencies using non-derivative net investment hedges in conjunction with borrowings under the multicurrency tranche of its 2015 Revolving Credit Facility. In March 2018, the Company entered into a non-derivative net investment hedge on its euro-denominated investment in the Gramercy European Property Fund III and in prior periods, from September 2015 until disposal of the underlying investments in July 2017, the Company had a non-derivative net investment hedge on its investments in the Gramercy European Property Fund and the Goodman Europe JV, all of which had euros as their functional currencies. The Company’s non-derivative net investment hedge on its British pound sterling-denominated investments, which was entered into in July 2016, is used to hedge exposure to changes in the British pound sterling U.S. dollar exchange rate underlying its unconsolidated equity investment in the Goodman UK JV, which has British pounds sterling as its functional currency. The Company’s non-derivative net investment hedge values are reported at carrying value and are included in the balance of the senior unsecured revolving credit facility on the Consolidated Balance Sheets. During the three and six months ended June 30, 2018 , the Company recorded a net gain of $1,027 and $568 , respectively, in other comprehensive income from the impact of exchange rates related to the non-derivative net investment hedges. During the three and six months ended June 30, 2017, the Company recorded a net loss of $4,196 and $5,119 , respectively, in other comprehensive income from the impact of exchange rates related to the non-derivative net investment hedges. When the non-derivative net investments being hedged are sold or substantially liquidated, the balance of the translation adjustment accumulated in other comprehensive income will be reclassified into earnings.

Shareholders' Equity (Deficit)

Shareholders' Equity (Deficit) of the Company	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Shareholders' Equity (Deficit) of the Company	Shareholders’ Equity (Deficit) of the Company As of June 30, 2018 and December 31, 2017 , the Company's authorized capital shares consisted of 500,000,000 shares of beneficial interest, $0.01 par value per share, of which the Company is authorized to issue up to 490,000,000 common shares of beneficial interest, $0.01 par value per share, or common shares, and 10,000,000 preferred shares of beneficial interest, $0.01 par value per share, or preferred shares. As of June 30, 2018 , 160,792,820 common shares and 3,500,000 preferred shares were issued and outstanding. During the six months ended June 30, 2018 , the Company’s common dividends were as follows: Quarter Ended Record Date Payment Date Common dividend per share March 31, 2018 3/30/2018 4/16/2018 $ 0.375 June 30, 2018 6/29/2018 7/16/2018 $ 0.375 Employee Share Purchase Plan In June 2017, the Company’s shareholders approved an Employee Share Purchase Plan, or ESPP, which enables the Company’s eligible employees to purchase the common shares through payroll deductions, subject to the restrictions in the Merger Agreement. The ESPP has a maximum of 250,000 common shares available for issuance and provides for eligible employees to purchase the common shares during defined offering periods at a purchase price determined at the discretion of the board of trustees, which was initially established to be equal to 90.0% of the lower of either (i) the closing price of the Company’s common shares on the first day of the offering period and (ii) the closing price of the Company’s common shares on the last day of the offering period. As of June 30, 2018 , there were 1,374 shares issued under the ESPP. As of June 30, 2018 , the ESPP has been suspended, subject to the terms of the Merger Agreement. Dividend Reinvestment Plan In June 2016, the Company adopted a dividend reinvestment plan, or DRIP, under which shareholders may use their dividends and optional cash payments to purchase additional common shares of the Company, subject to the restrictions in the Merger Agreement. In August 2016, the Company registered 3,333,333 common shares related to the DRIP. During the six months ended June 30, 2018 , 3,363 shares were issued under the DRIP and as of June 30, 2018 there were 3,322,410 shares available for issuance under the DRIP. At-The-Market Equity Offering Program In July 2016, the Company’s board of trustees approved the establishment of an “at the market” equity issuance program, or ATM Program, pursuant to which the Company may offer and sell common shares with an aggregate gross sales price of up to $375,000 , subject to the restrictions in the Merger Agreement. During the six months ended June 30, 2018 , the Company did not sell any common shares through the ATM Program. Preferred Shares Holders of the Company's Series A Preferred Shares are entitled to receive annual dividends of $1.78125 per share on a quarterly basis and dividends are cumulative, subject to certain provisions. On or after August 15, 2019, the Company can, at its option, redeem the Series A Preferred Shares at par for cash. At June 30, 2018 , the Company had 3,500,000 of its Series A Preferred Shares outstanding with a mandatory liquidation preference of $25.00 per share. Equity Incentive Plans In June 2016, the Company instituted its 2016 Equity Incentive Plan, which was approved by the Company’s board of trustees and shareholders. As of June 30, 2018 , there were 2,625,800 shares available for grant under the 2016 Equity Incentive Plan. The Company accounts for share-based compensation awards using fair value recognition provisions and assumes an estimated forfeiture rate which impacts the amount of compensation cost recognized over the benefit period. Through June 30, 2018 , 1,129,130 restricted shares had been issued under the Company’s equity incentive plans, including the 2016 Equity Incentive Plan and the Company’s previous equity incentive plans, of which 67.2% have vested. As of June 30, 2018 and December 31, 2017 , the Company had 341,089 and 347,676 weighted average restricted shares outstanding, respectively. Compensation expense of $617 and $1,158 was recorded for the three and six months ended June 30, 2018 , respectively, related to the Company’s equity incentive plans. Compensation expense of $755 and $1,572 was recorded for the three and six months ended June 30, 2017, respectively, related to the Company’s equity incentive plans. Compensation expense of $4,141 will be recorded over the course of the next 23 months representing the remaining weighted average vesting period of equity awards issued under the equity incentive plans as of June 30, 2018 . Compensation expense of $1,151 and $2,289 was recorded for the three and six months ended June 30, 2018 , respectively, for the Company's Outperformance Plans. Compensation expense of $1,070 and $2,126 was recorded for the three and six months ended June 30, 2017, respectively, for the Company's Outperformance Plans. Compensation expense of $9,037 will be recorded over the course of the next 32 months , representing the remaining weighted average vesting period of the awards issued under the Outperformance Plans as of June 30, 2018 . Earnings per Share The Company presents both basic and diluted earnings per share, or EPS. Basic EPS is computed by dividing net income available to common shareholders, as adjusted for unallocated earnings attributable to certain participating securities, if any, by the weighted average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common shares were exercised or converted into common shares, as long as their inclusion would not be anti-dilutive. The two-class method is an earnings allocation methodology that determines EPS for common shares and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The Company has certain share-based payment awards that contain nonforfeitable rights to dividends, which are considered participating securities for the purposes of computing EPS pursuant to the two-class method, and therefore the Company applies the two-class method in its computation of EPS. Earnings per share for the three and six months ended June 30, 2018 and 2017 are computed as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator – Income (loss): Net income (loss) from continuing operations $ 20,754 $ 5,985 $ 32,363 $ (2,087 ) Net loss from discontinued operations — (28 ) — (52 ) Net income (loss) before net gain on disposals 20,754 5,957 32,363 (2,139 ) Net gain on disposals 4,523 2,002 20,778 19,379 Net income 25,277 7,959 53,141 17,240 Less: Net (income) loss attributable to noncontrolling interest (845 ) 113 (1,647 ) (41 ) Less: Nonforfeitable dividends allocated to participating shareholders (206 ) (337 ) (409 ) (635 ) Less: Preferred share dividends (1,558 ) (1,558 ) (3,117 ) (3,117 ) Net income available to common shares outstanding $ 22,668 $ 6,177 $ 47,968 $ 13,447 Denominator – Weighted average shares: Basic weighted average shares outstanding 160,420,278 148,542,916 160,414,240 144,746,251 Effect of dilutive securities: Unvested non-participating share-based payment awards — 86,452 — 79,552 Options 13,073 19,196 11,051 14,471 Exchangeable Senior Notes — 1,265,879 — 1,125,662 Diluted weighted average shares outstanding 160,433,351 149,914,443 160,425,291 145,965,936 The Company’s options and other share-based payment awards used in the computation of EPS were calculated using the treasury share method. As discussed in Note 5 , 100.0% of the Company’s Exchangeable Senior Notes were exchanged for 5,258,420 of the Company’s common shares in September 2017, however for the three and six months ended June 30, 2017, the Company had the intent and ability to settle the debt component of the Exchangeable Senior Notes in cash and the excess conversion premium in shares, thus for that period the Company only included the effect of the excess conversion premium in the calculation of Diluted EPS. For the three and six months ended June 30, 2018 , the net income (loss) attributable to the outside interests in the Operating Partnership has been excluded from the numerator and 5,934,765 and 5,490,217 , respectively, weighted average shares related to the outside interests in the Operating Partnership have been excluded from the denominator for the purpose of calculating Diluted EPS as there would have been no effect had such amounts been included. For the three and six months ended June 30, 2017, the net income (loss) attributable to the outside interests in the Operating Partnership has been excluded from the numerator and 560,443 and 590,547 , respectively, weighted average shares related to the outside interests in the Operating Partnership have been excluded from the denominator for the purpose of calculating Diluted EPS as there would have been no effect had such amounts been included. Refer to Note 11 for more information on the outside interests in the Operating Partnership. Accumulated Other Comprehensive Income Accumulated other comprehensive income as of June 30, 2018 and December 31, 2017 is composed of the following: June 30, 2018 December 31, 2017 Net unrealized gain on derivative securities $ 42,670 $ 15,630 Net unrealized gain on debt instruments 1,036 417 Foreign currency translation adjustments: Net gain on non-derivative net investment hedges 1 865 297 Other foreign currency translation adjustments (6,966 ) (5,734 ) Reclassification of swap gain (loss) into interest expense (8,583 ) 2,166 Cumulative effect of accounting change 103 — Total accumulated other comprehensive income $ 29,125 $ 12,776 1. The foreign currency translation adjustment associated with the Company’s non-derivative net investment hedge related to its European investments is included in other comprehensive income. The balance reflects write-offs of $1,851 on the Company’s non-derivative net investment hedge during the year ended December 31, 2017 .

Partners' Capital of the Operat

Partners' Capital of the Operating Partnership	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Partners' Capital of the Operating Partnership	Partners’ Capital of the Operating Partnership The Company is the sole general partner of the Operating Partnership. As of June 30, 2018 , the Company owned 160,792,820 of the outstanding general and limited partnership interests, or 96.42% , of the Operating Partnership. The number of common units in the Operating Partnership is equivalent to the number of outstanding common shares of the Company, and the entitlement of all the Operating Partnership’s common units to quarterly distributions and payments in liquidation are substantially the same as those of the Company's common shareholders. Similarly, in the case of each series of preferred units in the Operating Partnership held by the Company, there is a series of preferred shares that is equivalent in number and carries substantially the same terms as such series of the Operating Partnership’s preferred units. Limited Partner Units As of June 30, 2018 , limited partners other than the Company owned 5,959,858 common units, or 3.58% , of the Operating Partnership. Earnings per Unit The Operating Partnership's earnings per unit for the three and six months ended June 30, 2018 and 2017 are computed as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator – Income (loss): Net income (loss) from continuing operations $ 20,754 $ 5,985 $ 32,363 $ (2,087 ) Net loss from discontinued operations — (28 ) — (52 ) Net income (loss) before net gain on disposals 20,754 5,957 32,363 (2,139 ) Net gain on disposals 4,523 2,002 20,778 19,379 Net income 25,277 7,959 53,141 17,240 Less: Net loss attributable to noncontrolling interest in other partnerships — 137 — 17 Less: Nonforfeitable dividends allocated to participating unitholders (206 ) (337 ) (409 ) (635 ) Less: Preferred unit distributions (1,558 ) (1,558 ) (3,117 ) (3,117 ) Net income available to common units outstanding $ 23,513 $ 6,201 $ 49,615 $ 13,505 Denominator – Weighted average units: Basic weighted average units outstanding 166,355,043 149,103,359 165,904,457 145,336,798 Effect of dilutive securities: Unvested non-participating share-based payment awards — 86,452 — 79,552 Options 13,073 19,196 11,051 14,471 Exchangeable Senior Notes — 1,265,879 — 1,125,662 Diluted weighted average units outstanding 166,368,116 150,474,886 165,915,508 146,556,483

Noncontrolling Interests

Noncontrolling Interests	6 Months Ended
	Jun. 30, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interests	Noncontrolling Interests Noncontrolling interests represent the outside equity interests in the Operating Partnership as well as third-party equity interests in the Company’s other consolidated subsidiaries. Outside Equity Interests in Operating Partnership The outside equity interests in the Operating Partnership include OP Units and earned and vested LTIP Units, which are convertible on a one-for-one basis into OP Units. The aggregate outstanding noncontrolling interest in the Operating Partnership as of June 30, 2018 represented an interest of approximately 3.58% in the Operating Partnership. A portion of the Operating Partnership’s net income (loss) during each reporting period is attributed to noncontrolling interests based on the weighted average percentage ownership of both OP Unit holders and earned and vested LTIP Unit holders relative to the sum of the Company’s total outstanding common shares, OP Units, and earned and vested LTIP Units. OP Units During the six months ended June 30, 2018 , the Company issued 1,566,961 OP Units as part of its contribution to fund its pro rata share of the E-Commerce JV’s acquisition of four properties. As of June 30, 2018 , 5,300,343 OP Units were outstanding, which can be redeemed for 5,300,343 of the Company's shares. During the six months ended June 30, 2018 and the year ended December 31, 2017 , 6,038 and 134,607 OP Units, respectively, were converted on a one-for-one basis into common shares of the Company. At June 30, 2018 , 5,300,343 common shares of the Company were reserved for issuance upon redemption of OP Units. OP Units are recorded at the greater of cost basis or fair market value based on the closing share price of the Company’s common shares at the end of the reporting period. As of June 30, 2018 , the value of the OP Units was $156,293 . LTIP Units As of June 30, 2018 , noncontrolling interest owners held 659,515 earned and vested LTIP Units, which, upon conversion into OP Units, can be redeemed for 659,515 of the Company’s common shares. During the six months ended June 30, 2018 and year ended December 31, 2017 , there were no earned and vested LTIP Units converted into OP Units or redeemed for common shares of the Company. At June 30, 2018 , 659,515 common shares of the Company were reserved for issuance upon conversion of the earned and vested LTIP Units into OP Units and their subsequent redemption for common shares. Below is the rollforward of the activity relating to the noncontrolling interests in the Operating Partnership as of June 30, 2018 : Noncontrolling Interest Balance at January 1, 2018 $ 113,530 Issuance of noncontrolling interests in the Operating Partnership 37,558 Redemption of noncontrolling interests in the Operating Partnership (130 ) Net income attribution 1,647 Fair value adjustments 7,448 Dividends (3,760 ) Balance at June 30, 2018 $ 156,293 Interests in Other Entities There are entities that the Company consolidates into its Consolidated Financial Statements based on the structure of the entities and their control provisions. As of June 30, 2018 , the Company consolidated the Lakemont Development Investment and during the year ended December 31, 2017 until its dissolution in the fourth quarter of 2017, the Company consolidated European Fund Manager, which were both consolidated VIEs of the Company. The Company’s interest in these entities is presented in the equity section of its Consolidated Financial Statements. Refer to Note 2 for further discussion of these entities and consolidation considerations.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Funding Commitments As of June 30, 2018 , the Company is obligated to fund the development of two properties and remaining improvements at two development properties, for which it has remaining cumulative future commitments of $40,265 . The Company has committed $61,730 ( €52,187 ) to the Gramercy European Property Fund III. The Company contributed $28,186 ( €23,478 ) to the Gramercy European Property Fund III as of June 30, 2018 . Foreign currency commitments have been converted into U.S. dollars based on (i) the foreign exchange rate at the closing date for completed transactions and (ii) the exchange rate that prevailed on June 30, 2018 , in the case of unfunded commitments. The Company has a 51.0% interest in the E-Commerce JV and has committed capital to fund its pro rata share of the E-Commerce JV’s initial acquisition of six properties, as well as the acquisition of additional properties in the future, subject to the partners' approval. The Company's pro rata funding commitment for the initial six properties is estimated at approximately $110,000 , which will be funded using a combination of OP Units and cash. As of June 30, 2018 , the Company contributed approximately $61,304 to the E-Commerce JV, of which $15,565 was contributed in cash. The Company committed to fund $100,000 to Strategic Office Partners, of which $32,427 was funded as of June 30, 2018 . In July 2018, the Company sold its 25.0% interest in Strategic Office Partners to TPG, and following the sale the Company has no outstanding commitment to Strategic Office Partners. Refer to Note 15 for more information on the transaction. See Note 4 for further information on the Gramercy European Property Fund III, the E-Commerce JV, and Strategic Office Partners. Legal Proceedings Gramercy and its board of trustees are named as defendants in three pending lawsuits brought by purported Gramercy shareholders challenging the proposed transaction between the Company and affiliates of Blackstone: Anderson v. Gramercy Property Trust et al., No. 1:18-cv-05335-PCK, a purported class action, was filed in the United States District Court for the Southern District of New York on June 13, 2018, Franchi v. Gramercy Property Trust et al., No. 1:18-cv-01842-ELH, a purported class action, was filed in the United States District Court for the District of Maryland on June 20, 2018, and Madry v. Gramercy Property Trust et al., No. 1:18-cv-01851-TDC, an individual action, was filed in the United States District Court for the District of Maryland on June 21, 2018. The complaints allege, among other things, that the individual defendants caused the Company to file a materially incomplete and misleading preliminary proxy statement relating to the proposed transaction in violation of Sections 14(a) and 20(a) of the Exchange Act. The Anderson and Madry complaints seek a variety of equitable and injunctive relief, including enjoining defendants from consummating the proposed merger transaction unless and until the Company provides supplemental disclosures, unspecified damages and, in the case of the Anderson complaint, rescission of the Merger Agreement or any of the terms thereof, or rescissory damages. The Franchi complaint seeks, among other relief, to enjoin defendants from proceeding with, consummating or closing the proposed merger transaction, rescission of the merger transaction or rescissory damages, and dissemination of a supplemental proxy statement. All three complaints also seek an award of attorneys’ and expert fees and expenses. The Company believes the lawsuits are without merit. The Company is unable to predict the outcome of these matters. In addition, the Company and/or one or more of its subsidiaries is party to various litigation matters that are considered routine litigation incidental to its or their business, none of which are considered material. Office Leases The Company has several office locations, which are each subject to operating lease agreements. These office locations include the Company’s corporate office at 90 Park Avenue, New York, New York, and the Company’s various regional offices located across the United States and Europe. Capital and Operating Ground Leases Certain properties acquired are subject to ground leases, which are accounted for as operating and capital leases, as applicable. The ground leases have varying ending dates, renewal options and rental rate escalations, with the latest lease extending to June 2053 . Future minimum rental payments to be made by the Company under these non-cancelable ground leases, excluding increases resulting from increases in the consumer price index, are as follows: July 1 to December 31, 2018 2019 2020 2021 2022 Thereafter Total Ground Leases - Operating $ 1,266 $ 2,593 $ 2,596 $ 2,567 $ 2,598 $ 73,175 $ 84,795 Ground Leases - Capital — — — — — 329 329 Total $ 1,266 $ 2,593 $ 2,596 $ 2,567 $ 2,598 $ 73,504 $ 85,124

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company has elected to be taxed as a REIT, under Sections 856 through 860 of the Internal Revenue Code beginning with its taxable year ended December 31, 2004. To qualify as a REIT, the Company must meet certain organizational and operational requirements, including a requirement to distribute annually at least 90.0% of its ordinary taxable income to its shareholders. As a REIT, the Company generally will not be subject to U.S. federal income tax on taxable income that it distributes to its shareholders. The Operating Partnership is a limited partnership and therefore is generally not liable for federal corporate income taxes as income is reported in the tax returns of its partners. The Operating Partnership may, however, be subject to certain state and local taxes. The Operating Partnership has in the past established taxable REIT subsidiaries, or TRSs, to effect various taxable transactions. Typical transactions that could cause these TRSs to be subject to federal, state and local taxes would include, but are not limited to, gains on property sales and management fee income. Tax expense from the Operating Partnership’s TRS for the three and six months ended June 30, 2018 and 2017 was immaterial. The Company’s policy for interest and penalties, if any, on material uncertain tax positions recognized in the financial statements is to classify these as interest expense and operating expense, respectively. As of June 30, 2018 and December 31, 2017 , the Company did not incur any material interest or penalties.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information The following table represents supplemental cash flow disclosures for the six months ended June 30, 2018 and 2017 : Six Months Ended June 30, 2018 2017 Supplemental cash flow disclosures: Interest paid $ 50,194 $ 44,441 Income taxes paid 218 296 Proceeds from 1031 exchanges from sale of real estate 5 170,210 Use of funds from 1031 exchanges for acquisitions of real estate (5 ) (140,987 ) Non-cash activity: Fair value adjustment to noncontrolling interest in the Operating Partnership $ 7,448 $ 576 Debt assumed in acquisition of real estate — 3,680 Debt transferred in disposition of real estate — (10,456 ) Non-cash acquisition of consolidated VIE — 24,930 Dividend reinvestment plan proceeds 81 103 Redemption of units of noncontrolling interest in the Operating Partnership for common shares (130 ) (2,697 ) Contributions to unconsolidated equity investments for units of noncontrolling interests in the operating partnership 37,558 —

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Subsequent to June 30, 2018, the Company sold its 25.0% interest in Strategic Office Partners to its investment partner, TPG, for gross proceeds of $45,382 in a transaction that valued the investment portfolio at an aggregate value of $ 388,000 . Also subsequent to June 30, 2018, the Company closed on the disposition of two properties for gross proceeds of approximately $36,650 .

Significant Accounting Polici24

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Quarterly Presentation The accompanying Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In management’s opinion, all adjustments (consisting of normal recurring accruals) considered necessary for fair presentation have been included. The 2018 operating results for the period presented are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . These Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Annual Report on Form 10-K for the year ended December 31, 2017 of the Company and the Operating Partnership. The Consolidated Balance Sheets at December 31, 2017 were derived from the audited Consolidated Financial Statements at that date.
Reclassifications	Reclassifications Certain prior year balances have been reclassified to conform with the current year presentation. During the fourth quarter of 2017, the Company adopted Accounting Standards Update, or ASU, No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, which requires restricted cash and cash equivalents to be included with cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the Consolidated Statements of Cash Flows. As a result of the adoption, net cash provided by operating activities changed by $19 , net cash used in investing activities changed by $26,523 , and net cash provided by financing activities changed by $880 , for the six months ended June 30, 2017 .
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements include the Company’s accounts and those of the Company’s subsidiaries which are wholly-owned or controlled by the Company, or entities which are variable interest entities, or VIEs, in which the Company is the primary beneficiary. The primary beneficiary is the party that absorbs a majority of the VIE’s anticipated losses and/or a majority of the expected returns. The Company has evaluated its investments for potential classification as variable interests by evaluating the sufficiency of each entity’s equity investment at risk to absorb losses. Entities which the Company does not control and are considered VIEs, but for which the Company is not the primary beneficiary, are accounted for under the equity method. All significant intercompany balances and transactions have been eliminated. The equity interests of other limited partners in the Company’s Operating Partnership are reflected as noncontrolling interests.
Real Estate Investments	Real Estate Investments Real Estate Acquisitions The Company evaluates its acquisitions of real estate, including equity interests in entities that predominantly hold real estate assets, to determine if the acquired assets meet the definition of a business and need to be accounted for as a business combination, or alternatively, should be accounted for as an asset acquisition. An integrated set of assets and activities acquired does not meet the definition of a business if either (i) substantially all the fair value of the gross assets acquired is concentrated in either a single identifiable asset or a group of similar identifiable assets, or (ii) the asset and activities acquired do not contain at least an input and a substantive process that together significantly contribute to the ability to create outputs. The Company expects that its acquisitions of real estate will continue to not meet the definition of a business. Acquisitions of real estate that do not meet the definition of a business, including sale-leaseback transactions that have newly-originated leases and real estate investments under construction, or build-to-suit investments, are recorded as asset acquisitions. The accounting for asset acquisitions is similar to the accounting for business combinations, except that the acquisition consideration, including acquisition costs, is allocated to the individual assets acquired and liabilities assumed on a relative fair value basis. Based on this allocation methodology, asset acquisitions do not result in the recognition of goodwill or a bargain purchase. The Company incurs internal transaction costs, which are direct, incremental internal costs related to acquisitions, that are recorded within general and administrative expense. Additionally, for build-to-suit investments in which the Company may engage a developer to construct a property or provide funds to a tenant to develop a property, the Company capitalizes the funds provided to the developer/tenant and real estate taxes, if applicable, during the construction period. To determine the fair value of assets acquired and liabilities assumed in an acquisition, which generally include land, building, improvements, and intangibles, such as the value of above- and below-market leases and origination costs associated with the in-place leases at the acquisition date, the Company utilizes various estimates, processes and information to determine the as-if-vacant property value. Estimates of value are made using customary methods, including data from appraisals, comparable sales, and discounted cash flow analyses. Estimates of future cash flows are based on a number of factors including the historical operating results, known trends, and market/economic conditions that may affect the property. The Company assesses the fair value of leases assumed at acquisition based upon estimated cash flow projections that utilize appropriate discount rates and available market information. Refer to the policy section "Intangible Assets and Liabilities" for more information on the Company’s accounting for intangibles. Depreciation is computed using the straight-line method over the shorter of the estimated useful life at acquisition of the capitalized item or 40 years for buildings, five to ten years for building equipment and fixtures, and the lesser of the useful life or the remaining lease term for tenant improvements and leasehold interests. Maintenance and repair expenditures are expensed as incurred. For transactions that qualify as business combinations, the Company recognizes the assets acquired and liabilities assumed at fair value, including the value of intangible assets and liabilities, and any excess or deficit of the consideration transferred relative to the fair value of the net assets acquired is recorded as goodwill or a bargain purchase gain, as appropriate. Acquisition costs of business combinations are expensed as incurred. Capital Improvements In leasing space, the Company may provide funding to the lessee through a tenant allowance. Certain improvements are capitalized when they are determined to increase the useful life of the building. During construction of qualifying projects, the Company capitalizes project management fees as permitted to be charged under the lease, if incremental and identifiable. In accounting for tenant allowances, the Company determines whether the allowance represents funding for the construction of leasehold improvements and evaluates the ownership of such improvements. If the Company is considered the owner of the leasehold improvements, the Company capitalizes the amount of the tenant allowance and depreciates it over the shorter of the useful life of the leasehold improvements or the lease term. If the tenant allowance represents a payment for a purpose other than funding leasehold improvements, or in the event the Company is not considered the owner of the improvements for accounting purposes, the allowance is considered to be a lease incentive and is recognized over the lease term as a reduction of rental revenue. Impairments and Disposals The Company reviews the recoverability of a property’s carrying value when circumstances indicate a possible impairment of the value of a property, such as an adverse change in future expected occupancy or a significant decrease in the market price of an asset. The review of recoverability is based on an estimate of the future undiscounted cash flows, excluding interest charges, expected to result from the property’s use and eventual disposition. These estimates consider factors such as changes in strategy resulting in an increased or decreased holding period, expected future operating income, market and other applicable trends and residual value, as well as the effects of leasing demand, competition and other factors. If management determines impairment exists due to the inability to recover the carrying value of a property, for properties to be held and used, an impairment loss is recorded to the extent that the carrying value exceeds the estimated fair value of the property, and for assets held for sale, an impairment loss is recorded to the extent that the carrying value exceeds the fair value less the estimated cost of disposal. These assessments are recorded as an impairment loss in the Consolidated Statements of Operations in the period the determination is made. The estimated fair value of the asset becomes its new cost basis. For a depreciable long-lived asset to be held and used, the new cost basis will be depreciated or amortized over the remaining useful life of that asset. The Company recognizes sales of real estate properties upon closing, at which time the Company transfers control of the assets to the purchaser. Payments received from purchasers prior to closing are recorded as deposits. Profit on real estate sold is based on the transaction price and is recognized using the full accrual method upon closing.
Cash and Cash Equivalents	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents. The Company's restricted cash primarily consists of reserves for certain capital improvements, leasing, interest and real estate tax and insurance payments as required by certain mortgage note obligations, as well as proceeds from property sales held by qualified intermediaries to be used for tax-deferred, like-kind exchanges under section 1031 of the Internal Revenue Code of 1986, as amended, or the Internal Revenue Code. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sums to the total of the same such amounts shown in the Consolidated Statements of Cash Flows. As of June 30, 2018 2017 Cash and cash equivalents $ 59,741 $ 163,509 Restricted cash 12,026 40,326 Total cash, cash equivalents, and restricted cash $ 71,767 $ 203,835
Variable Interest Entities, Consolidated and Unconsolidated	Variable Interest Entities The Company had five consolidated VIEs and two unconsolidated VIEs as of June 30, 2018 and December 31, 2017 , which were determined based on the structure and control provisions of each entity. The Company’s five consolidated VIEs as of June 30, 2018 and December 31, 2017 included the Operating Partnership and four land parcels in Fort Mill, South Carolina acquired by an investment entity formed in December 2017, on which it will fund the development of four industrial facilities, or the Lakemont Development Investment. The Company has a 95.0% interest in the Lakemont Development Investment and will acquire the seller’s retained 5.0% interest when the properties are developed and leased. As of June 30, 2018 and December 31, 2017 , the Company’s carrying value of the Lakemont Development Investment was $4,765 and $4,584 , respectively. The Company’s two unconsolidated VIEs as of June 30, 2018 and December 31, 2017 included its retained non-investment grade subordinate bonds, preferred shares and ordinary shares of two collateralized debt obligations, or CDOs, which are collectively herein referred to as the Retained CDO Bonds. Refer to the “Other Assets” section of this Note 2 and also to Note 7 for more information on the accounting and valuation of the Retained CDO Bonds. As of June 30, 2018 and December 31, 2017 , the Company’s carrying value of the Retained CDO Bonds was $6,792 and $5,527 , respectively.
Tenant and Other Receivables	Tenant and Other Receivables Tenant and other receivables are derived from rental revenue, tenant reimbursements, and management fees. Rental revenue is recorded on a straight-line basis over the initial term of the lease. Since many leases provide for rental increases at specified intervals, straight-line basis accounting requires the Company to record a receivable, and include in revenues, unbilled rent receivables that will only be received if the tenant makes all rent payments required through the expiration of the initial term of the lease. Tenant and other receivables also include receivables related to tenant reimbursements for common area maintenance expenses and certain other recoverable expenses that are recognized as revenue in the period in which the related expenses are incurred. Tenant and other receivables are recorded net of the allowance for doubtful accounts, which as of June 30, 2018 and December 31, 2017 was $692 and $638 , respectively. The Company continually reviews receivables related to rent, tenant reimbursements, and management fees, including incentive fees, and determines collectability by taking into consideration the tenant or asset management clients’ payment history, the financial condition of the tenant or asset management client, business conditions in the industry in which the tenant or asset management client operates and economic conditions in the area in which the property or asset management client is located. In the event that the collectability of a receivable is in doubt, the Company increases the allowance for doubtful accounts or records a direct write-off of the receivable, as appropriate.
Intangible Assets and Liabilities	Intangible Assets and Liabilities As discussed above in policy section, "Real Estate Acquisitions," the Company follows the acquisition method of accounting for its asset acquisitions and business combinations and thus allocates the purchase price of acquired properties to tangible and identifiable intangible assets acquired based on their respective fair values. Identifiable intangible assets include amounts allocated to acquired leases for above- and below-market lease rates and the value of in-place leases. Management also considers information obtained about each property as a result of its pre-acquisition due diligence. Above-market and below-market lease values for properties acquired are recorded based on the present value of the difference between the contractual amount to be paid pursuant to each in-place lease and management’s estimate of the fair market lease rate for each such in-place lease, measured over a period equal to the remaining non-cancelable term of the lease. The present value calculation utilizes a discount rate that reflects the risks associated with the leases acquired. The above-market and below-market lease values are amortized as a reduction of and increase to rental revenue, respectively, over the remaining non-cancelable terms of the respective leases. If a tenant terminates its lease prior to its contractual expiration and no future rental payments will be received, any unamortized balance of the market lease intangibles will be written off to rental revenue. The aggregate value of in-place leases represents the costs of leasing costs, other tenant related costs, and lost revenue that the Company did not have to incur by acquiring a property that is already occupied. Factors considered by management in its analysis of the in-place lease intangibles include an estimate of carrying costs during the expected lease-up period for each property taking into account current market conditions and costs to execute similar leases. In estimating carrying costs, management includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the anticipated lease-up period. Management also estimates costs to execute similar leases including leasing commissions and other related expenses. The value of in-place leases is amortized to depreciation and amortization expense over the remaining non-cancelable term of the respective leases. In no event does the amortization period for intangible assets exceed the remaining depreciable life of the building. If a tenant terminates its lease prior to its contractual expiration and no future rental payments will be received, any unamortized balance of the in-place lease intangible will be written off to depreciation and amortization expense. Above-market and below-market ground rent intangibles are recorded for properties acquired in which the Company is the lessee pursuant to a ground lease assumed at acquisition. The above-market and below-market ground rent intangibles are valued similarly to above-market and below-market leases, except that, because the Company is the lessee as opposed to the lessor, the above-market and below-market ground lease values are amortized as a reduction of and increase to rent expense, respectively, over the remaining non-cancelable terms of the respective leases.
Revenue Recognition	Revenue Adoption of ASC Topic 606, "Revenue from Contracts with Customers" The Company adopted ASC Topic 606, which is described below in the section “Recently Issued Accounting Pronouncements,” on January 1, 2018 using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under the new guidance, while prior period amounts are not adjusted and continue to be reported in accordance with the historic accounting guidance in ASC Topic 605. As a result of adoption, the Company recorded an increase to its opening retained earnings balance of $663 as of January 1, 2018, which represents the cumulative impact of the new guidance and is related to the Company’s sale of real estate to Strategic Office Partners in 2016. There was no impact to revenues recorded for the three and six months ended June 30, 2018 as a result of adoption of the new revenue guidance. Revenue Recognition The Company recognizes revenue when control of the promised goods or services is transferred to a customer, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company’s primary sources of revenue include rental revenue, operating expense reimbursements, third-party management fees, and other income, which are disaggregated on the Consolidated Statements of Operations and are described in detail below. Real Estate Investments Rental revenue from leases on real estate investments is recognized on a straight-line basis over the term of the lease, regardless of when payments are contractually due. For leases on properties that are under construction at the time of acquisition, the Company begins recognition of rental revenue upon completion of construction of the leased asset and delivery of the leased asset to the tenant. The Company’s lease agreements with tenants also generally contain provisions that require tenants to reimburse the Company for real estate taxes, insurance costs, common area maintenance costs, and other property-related expenses. Under lease arrangements in which the Company is the primary obligor for these expenses, the Company recognizes such amounts as both revenues and operating expenses. Under lease arrangements in which the tenant pays these expenses directly, such amounts are not included in revenues or expenses. These reimbursement amounts are recognized in the period in which the related expenses are incurred. Management Fees The Company’s asset and property management agreements may contain provisions for fees related to dispositions, administration of the assets including fees related to accounting, valuation and legal services, and management of capital improvements or projects on the underlying assets. The Company recognizes revenue for fees pursuant to its management agreements in the period in which they are earned. Deferred revenue from management fees received prior to the date earned are included in other liabilities on the Consolidated Balance Sheets. For management fee agreements that include multiple performance obligations, the Company allocates revenue to each performance obligation based on its relative standalone selling price, which is primarily determined based on the prices charged to customers. Certain of the Company’s asset management contracts and agreements with its unconsolidated equity investments include provisions that allow it to earn additional fees, generally described as incentive fees or promoted interests, based on the achievement of a targeted valuation or the achievement of a certain internal rate of return on the managed assets held by third parties or the equity investment. The Company’s incentive fees are accounted for as variable consideration and revenue is recognized for them based on the Company’s estimate of the expected amount to which it will be entitled in exchange for its services. The Company recognizes promoted interest in the period in which it is determined to be appropriately earned pursuant to the terms of the specific agreement. The values of incentive fees and promoted interest fees are periodically evaluated by management. Other Income Other income primarily consists of income accretion on the Company’s Retained CDO Bonds, realized foreign currency exchange gains (losses), and interest income.
Foreign Currency	Foreign Currency The Company's European management platform performs asset and property management services in Europe. The Company has unconsolidated equity investments in Europe and Asia and previously had two wholly-owned properties in Canada until their dispositions in March 2017. The Company also has borrowings outstanding in euros and British pounds sterling under the multicurrency portion of its revolving credit facility. Refer to Note 4 for more information on the Company’s foreign unconsolidated equity investments.
Other Assets	Other Assets The Company includes prepaid expenses, capitalized software costs, contract intangible assets, deferred costs, loan investments, goodwill, derivative assets, and Retained CDO Bonds in other assets. Loan Investments The Company may originate loans related to specific real estate development projects. In October 2017, the Company entered into an agreement to provide a mezzanine construction loan facility with a maximum commitment of $250,000 to an industrial developer as borrower. As of June 30, 2018 and December 31, 2017, the carrying value of the Company’s loan investments was $33,169 and $22,154 , respectively, which represents the cost, net of accumulated amortization of loan costs. A s of June 30, 2018 , the loan investments had a weighted average interest rate of 11.36% . The Company evaluates its loan investments for possible credit losses each period. There were no loan reserves recorded during the three and six months ended June 30, 2018 and all of the Company’s loan investments were performing in accordance with the terms of the relevant investments as of June 30, 2018 .
Goodwill	Goodwill The Company recognized goodwill of $3,802 related to the acquisition of Gramercy Europe Limited in December 2014, which it adjusts each reporting period for the effect of foreign currency translation adjustments and tests for impairment on an annual basis, or more frequently if events or changes in circumstances indicate that the asset might be impaired. Based on the prevailing operating results and projected outlook for Gramercy Europe Limited as of June 30, 2018 , the Company determined the fair value of Gramercy Europe Limited was less than its carrying value and thus recorded an impairment loss of $3,293 on its goodwill during the three and six months ended June 30, 2018 . The fair value of Gramercy Europe Limited was determined using the income approach, wherein projections of discounted cash flows were based on factors such as forecasts of future real estate investments, operating results, management fees, and discount, promote hurdle and capitalization rates. The carrying value of goodwill at June 30, 2018 and December 31, 2017 was $0 and $3,272 , respectively.
Retained CDO Bonds	Retained CDO Bonds The Retained CDO Bonds are non-investment grade subordinate bonds, preferred shares and ordinary shares of two CDOs. Management estimated the timing and amount of cash flows expected to be collected and recognized an investment in the Retained CDO Bonds equal to the net present value of these discounted cash flows. There is no guarantee that the Company will realize any proceeds from this investment, or what the timing will be for the expected remaining life of the Retained CDO Bonds. The Company considers these investments to be not of high credit quality and does not expect a full recovery of interest and principal. Therefore, the Company has suspended interest income accruals on these investments. The Company classifies the Retained CDO Bonds as available for sale. On a quarterly basis, the Company evaluates the Retained CDO Bonds to determine whether significant changes in estimated cash flows or unrealized losses on these investments, if any, reflect a decline in value which is other-than-temporary. If there is a decrease in estimated cash flows and the investment is in an unrealized loss position, the Company will record an other-than-temporary impairment, or OTTI, in the Consolidated Statements of Operations. To determine the component of the OTTI related to expected credit losses, the Company compares the amortized cost basis of the Retained CDO Bonds to the present value of the revised expected cash flows, discounted using the pre-impairment effective yield. Conversely, if the security is in an unrealized gain position and there is a decrease or significant increase in expected cash flows, the Company will prospectively adjust the yield using the effective yield method. Refer to Note 7 for further discussion regarding the fair value measurement of the Retained CDO Bonds.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash investments, debt investments and accounts receivable. The Company places its cash investments in excess of insured amounts with high quality financial institutions. Concentrations of credit risk also arise when a number of the Company’s tenants or asset management clients are engaged in similar business activities or are subject to similar economic risks or conditions that could cause their inability to meet contractual obligations to the Company. The Company regularly monitors its portfolio to assess potential concentrations of credit risk. Management believes the current credit risk portfolio is reasonably well diversified. During the three and six months ended June 30, 2018 , there were no tenants that accounted for 10.0% or more of the Company's rental revenue. Additionally, during the three and six months ended June 30, 2018 , there were two states, Illinois and Texas , that each accounted for 10.0% or more of the Company’s rental revenue.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09 (Topic 606), Revenue from Contracts with Customers, which is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to customers in an amount reflecting the consideration it expects to receive in exchange for those goods or services. In April 2016 and February 2017, the FASB issued ASU 2016-10 and ASU 2017-05, respectively, which further clarified the new revenue recognition guidance under ASC Topic 606. The Company adopted the guidance on January 1, 2018 using the modified retrospective method, which did not have a material impact on its Consolidated Financial Statements. Refer to the “Revenue” section above for further detail. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities. The guidance requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and to record changes in instruments specific credit risk for financial liabilities measured under the fair value option in other comprehensive income. The update is effective for fiscal years beginning after December 15, 2017, and for interim periods therein. The Company adopted this standard in the first quarter of 2018 and the adoption did not have a material impact on its Consolidated Financial Statements. Refer to Note 8 for more information. I n February 2016, the FASB issued ASU 2016-02, Leases, which amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting. The update will be effective beginning in the first quarter of 2019 and early adoption is permitted. The new standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. The Company’s accounting for leases in which it is a lessor, which represents most of its leasing arrangements, will be largely unchanged under ASU 2016-02; however, the Company is a lessee in several operating and ground leases and the accounting for these arrangements is more significantly impacted by the new standard. Pursuant to the new guidance, lessees are required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. The Company is continuing to evaluate the impact of adopting the new leases standard on its Consolidated Financial Statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows Classification of Certain Cash Receipts and Cash Payments, which serves to reduce the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The update is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The Company adopted this standard in the first quarter of 2018 and the adoption did not have a material impact on its Consolidated Financial Statements. In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation: Scope of Modification Accounting. The amendment provides guidance on determining which changes to the terms and conditions of share-based payment awards require an entity to apply modification accounting. The guidance is effective for annual and interim periods beginning after December 15, 2017, with early adoption permitted under certain circumstances. The Company adopted this standard in the first quarter of 2018 and the adoption did not have a material impact on its Consolidated Financial Statements. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities. The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. The transition guidance provides companies with the option of early adopting the new standard using a modified retrospective transition method in any interim period after issuance of the update, or alternatively requires adoption for fiscal years beginning after December 15, 2018. In the first quarter of 2018, the Company early adopted this standard and the adoption did not have a material impact on its Consolidated Financial Statements.

Real Estate Investments Real Es

Real Estate Investments Real Estate Investments (Tables)	6 Months Ended
	Jun. 30, 2018
Real Estate [Abstract]
Schedule of Real Estate Investments	Investments in real estate properties consisted of the following: June 30, 2018 December 31, 2017 Square feet 1 Number of properties Investment Square feet 1 Number of properties Investment Operating properties 2 81,134,150 353 $ 5,828,172 82,146,063 363 $ 5,857,906 Land parcels 2 7,075 2 7,075 Less accumulated depreciation (410,020 ) (333,151 ) Total operating properties and land parcels $ 5,425,227 $ 5,531,830 Development properties 1,653,300 6 22,625 1,630,022 6 22,843 Total 82,787,450 361 $ 5,447,852 83,776,085 371 $ 5,554,673 1. Represents rentable square feet for operating properties and projected rentable square feet upon completion for development properties. 2. Includes development properties that have been completed as of the end of the period.
Summary of Acquisitions	Real estate acquisition activity for the three and six months ended June 30, 2018 and 2017 was as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Number of operating properties 2 10 3 17 Number of land parcels — 2 — 2 Rentable square feet of operating properties 388,466 2,493,043 550,522 4,750,354 Total purchase price of all acquisitions $ 22,140 $ 177,740 $ 32,690 $ 302,412
Summary of Dispositions	Real estate disposition activity for the three and six months ended June 30, 2018 and 2017 was as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Number of properties 1,2 9 10 14 17 Rentable square feet 343,966 1,739,881 1,890,057 2,227,753 Gross proceeds $ 19,971 $ 183,302 $ 130,983 $ 234,985 Impairment of real estate investments related to asset dispositions during the period 3 $ — $ 528 $ — $ 13,299 Net gain on disposals $ 4,523 $ 2,002 $ 20,778 $ 19,379 1. During the three and six months ended June 30, 2018, the Company sold nine and 14 properties, respectively, and also sold a land parcel that was part of another asset. 2. During the three and six months ended June 30, 2017, the Company sold 10 and 17 properties, respectively, as well as two offices that were part of another asset. 3. Although there were no impairments recognized related to assets disposed during the three and six months ended June 30, 2018, as presented in the table, the Company recognized impairments of $1,308 during these periods related to two properties held as of June 30, 2018 that were determined to have non-recoverable declines in value. In addition to the impairments recognized related to assets disposed during the three and six months ended June 30, 2017, as presented in the table, the Company recognized impairments of $5,052 during these periods related to three properties held as of June 30, 2017 that were determined to have non-recoverable declines in value.
Summary of Intangibles	Intangible assets and liabilities as of June 30, 2018 and December 31, 2017 consisted of the following: Weighted average amortization period (years) June 30, 2018 December 31, 2017 Intangible assets: In-place leases, net of accumulated amortization of $236,602 and $194,836 9.4 $ 490,350 $ 545,782 Above-market leases, net of accumulated amortization of $28,930 and $25,229 7.2 41,700 46,713 Below-market ground rent, net of accumulated amortization of $458 and $408 17.3 5,774 6,064 Total intangible assets $ 537,824 $ 598,559 Intangible liabilities: Below-market leases, net of accumulated amortization of $32,733 and $28,516 39.4 $ 141,929 $ 159,652 Above-market ground rent, net of accumulated amortization of $569 and $462 31.8 6,732 6,839 Total intangible liabilities $ 148,661 $ 166,491
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table provides the projected amortization expense of the intangible assets and liabilities for the next five years: July 1 to December 31, 2018 2019 2020 2021 2022 Depreciation and amortization expense $ 44,977 $ 81,899 $ 70,915 $ 60,426 $ 47,619 Rental revenue increase $ (3,271 ) $ (2,854 ) $ (3,559 ) $ (3,450 ) $ (5,467 )

Significant Accounting Polici26

Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sums to the total of the same such amounts shown in the Consolidated Statements of Cash Flows. As of June 30, 2018 2017 Cash and cash equivalents $ 59,741 $ 163,509 Restricted cash 12,026 40,326 Total cash, cash equivalents, and restricted cash $ 71,767 $ 203,835
Schedule of Retained Collateralized Debt Obligation Bonds	A summary of the Company’s Retained CDO Bonds as of June 30, 2018 is as follows: Number of Securities Face Value Amortized Cost Gross Unrealized Gain Other-Than-Temporary Impairment Fair Value Weighted Average Expected Life (years) 6 $ 332,360 $ 5,756 $ 1,036 $ — $ 6,792 0.8

Unconsolidated Equity Investm27

Unconsolidated Equity Investments (Tables)	6 Months Ended
	Jun. 30, 2018
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]
Equity Method Investments	As of June 30, 2018 and December 31, 2017 , the Company owned properties through unconsolidated equity investments and had investment interests in these unconsolidated entities as follows: As of June 30, 2018 As of December 31, 2017 Investment Ownership % Voting Interest % Partner Investment in Unconsolidated Equity Investment 1 No. of Properties Investment in Unconsolidated Equity Investment 1 No. of Properties Strategic Office Partners 25.0% 25.0% TPG Real Estate $ 31,512 14 $ 28,243 13 E-Commerce JV 51.0% 50.0% Ample Glow Investments 70,475 4 17,798 — Gramercy European Property Fund III 19.9% 50.0% Various 27,045 13 2,949 — Goodman UK JV 80.0% 50.0% Goodman Group 13,480 1 15,768 1 Other 2 5.1% - 50.0% 5.1% - 50.0% Various 4,770 2 5,456 3 Total $ 147,282 34 $ 70,214 17 1. The amounts presented include a basis difference of $431 and $1,943 , net of accumulated amortization, for the Goodman UK JV as of June 30, 2018 and December 31, 2017 , respectively. The amounts presented include a basis difference of $(8,100) , net of accumulated amortization, for the E-Commerce JV as of June 30, 2018 . 2. As of June 30, 2018 , includes CBRE Strategic Partners Asia and the Morristown JV. As of December 31, 2017 , includes CBRE Strategic Partners Asia, the Philips JV, and the Morristown JV.
Summary Investment Holdings	The following is a summary of the Company’s unconsolidated equity investments for the six months ended June 30, 2018 : Unconsolidated Equity Investments Balance at January 1, 2018 $ 70,214 Contributions to unconsolidated equity investments 81,356 Equity in net loss of unconsolidated equity investments, including adjustments for basis differences (2,764 ) Other comprehensive loss of unconsolidated equity investments (1,632 ) Distributions from unconsolidated equity investments (555 ) Cumulative effect of accounting change 663 Balance at June 30, 2018 $ 147,282
Schedule of Combined Balance Sheet for the Company's Joint Venture	The following are the balance sheets for the Company’s unconsolidated equity investments at June 30, 2018 : Strategic Office Partners E-Commerce JV Gramercy European Property Fund III Goodman UK JV Other 1 Assets: Real estate assets, net 2 $ 277,863 $ 302,636 $ 314,022 $ 16,122 $ 60,361 Other assets 88,048 62,200 68,677 921 15,628 Total assets $ 365,911 $ 364,836 $ 382,699 $ 17,043 $ 75,989 Liabilities and members' equity: Mortgage notes payable $ 226,427 $ 216,863 $ 238,339 $ — $ — Other liabilities 14,009 9,786 8,253 — 15,793 Total liabilities 240,436 226,649 246,592 — 15,793 Company's equity 31,512 70,475 27,045 13,480 4,770 Other members' equity 93,963 67,712 109,062 3,563 55,426 Liabilities and members' equity $ 365,911 $ 364,836 $ 382,699 $ 17,043 $ 75,989 1. Includes CBRE Strategic Partners Asia and the Morristown JV. 2. Includes basis adjustments recorded by the Company to adjust the unconsolidated equity investments to fair value. The following are the balance sheets for the Company’s unconsolidated equity investments at December 31, 2017 : Strategic Office Partners E-Commerce JV Goodman UK JV Other 1 Assets: Real estate assets, net 2 $ 265,014 $ — $ 18,633 $ 107,949 Other assets 78,243 35,727 1,473 34,022 Total assets $ 343,257 $ 35,727 $ 20,106 $ 141,971 Liabilities and members' equity: Mortgage notes payable $ 213,205 $ — $ — $ 38,662 Other liabilities 15,002 830 203 19,329 Total liabilities 228,207 830 203 57,991 Company's equity 28,243 17,798 15,768 8,405 Other members' equity 86,807 17,099 4,135 75,575 Liabilities and members' equity $ 343,257 $ 35,727 $ 20,106 $ 141,971 1. Includes CBRE Strategic Partners Asia, the Philips JV, the Morristown JV, and the Gramercy European Property Fund III. 2. Includes basis adjustments recorded by the Company to adjust the unconsolidated equity investments to fair value.
Schedule of Long-term Debt	Outstanding Balance 2 Property Unconsolidated Equity Investment Economic Ownership Interest Rate 1 Maturity Date June 30, 2018 December 31, 2017 Gramercy European Property Fund III Bridge Facility 3 Gramercy European Property Fund III 19.9% 1.50% 9/26/2019 $ 49,715 $ — Strategic Office Partners Facility 1 4 Strategic Office Partners 25.0% 5.02% 10/7/2019 169,380 169,380 Strategic Office Partners Facility 2 4 Strategic Office Partners 25.0% 6.03% 10/8/2020 52,020 39,540 E-Commerce JV Facility 4 E-Commerce JV 51.0% 3.38% 2/10/2023 220,000 — Gramercy European Property Fund III Facility 1 4 Gramercy European Property Fund III 19.9% 1.54% 3/12/2023 45,685 — Solingen, Germany Gramercy European Property Fund III 19.9% 1.66% 3/31/2023 9,785 — Gramercy European Property Fund III Facility 2 4 Gramercy European Property Fund III 19.9% 1.18% 6/22/2023 126,538 — Offenau, Germany Gramercy European Property Fund III 19.9% 1.89% 6/30/2023 9,125 — Henderson, NV Strategic Office Partners 25.0% 4.75% 8/6/2025 8,551 8,636 Total mortgage notes payable $ 690,799 $ 217,556 Net deferred financing costs and net debt discount (9,170 ) (4,351 ) Total mortgage notes payable, net $ 681,629 $ 213,205 1. Represents the current effective rate as of June 30, 2018 , including the swapped interest rate for mortgage notes that have interest rate swaps. The current interest rate is not adjusted to include the amortization of fair market value premiums or discounts. 2. Mortgage notes are presented at 100.0% of the amount held by the unconsolidated equity investment. 3. Represents the loan facility that is used to generate bridge financing for acquisitions and working capital needs of the Gramercy European Property Fund III. 4. As of June 30, 2018 , there were ten properties under the Strategic Office Partners Facility 1, three properties under the Strategic Office Partners Facility 2, four properties under the E-Commerce JV Facility, four properties under the Gramercy European Property Fund III Facility 1, and seven properties under the Gramercy European Property Fund III Facility 2.
Schedule of Combined Income Statement for the Company's Joint Venture	The following are the statements of operations for the Company’s unconsolidated equity investments for the three months ended June 30, 2018 : Strategic Office Partners E-Commerce JV Gramercy European Property Fund III Goodman UK JV Other 1 Revenues $ 11,765 $ 6,771 $ 1,730 $ 180 $ (5,632 ) Operating expenses 4,328 1,703 376 105 272 Interest expense 3,390 2,003 450 — — Depreciation and amortization 5,148 2,855 761 210 20 Total expenses 12,866 6,561 1,587 315 292 Net income (loss) from operations (1,101 ) 210 143 (135 ) (5,924 ) Gain (loss) on derivatives 177 — (781 ) — — Loss on extinguishment of debt — — (461 ) — — Provision for taxes — — (36 ) — — Net income (loss) $ (924 ) $ 210 $ (1,135 ) $ (135 ) $ (5,924 ) Company's share in net income (loss) $ (92 ) $ 260 $ (184 ) $ (108 ) $ (312 ) Adjustments for REIT basis 2 — 63 — (1,465 ) — Company's equity in net income (loss) within continuing operations $ (92 ) $ 323 $ (184 ) $ (1,573 ) $ (312 ) 1. Includes CBRE Strategic Partners Asia and the Morristown JV. 2. Goodman UK JV amount includes write-down of $1,462 recorded on the Company’s outside basis during the three months ended June 30, 2018 related to its accumulated foreign currency translation adjustments recorded on the investment. The following are statements of operations for the Company’s unconsolidated equity investments for the six months ended June 30, 2018 : Strategic Office Partners E-Commerce JV Gramercy European Property Fund III Goodman UK JV Other 1 Revenues $ 22,908 $ 8,936 $ 2,212 $ 180 $ (3,638 ) Operating expenses 8,479 2,286 1,058 365 378 Interest expense 6,503 2,672 547 — 666 Depreciation and amortization 9,971 3,717 970 416 353 Total expenses 24,953 8,675 2,575 781 1,397 Net income (loss) from operations (2,045 ) 261 (363 ) (601 ) (5,035 ) Gain (loss) on derivatives 669 — (781 ) — — Loss on extinguishment of debt — (1,200 ) (461 ) — — Provision for taxes — — (36 ) — — Net loss $ (1,376 ) $ (939 ) $ (1,641 ) $ (601 ) $ (5,035 ) Company’s share in net loss $ (66 ) $ (260 ) $ (277 ) $ (481 ) $ (292 ) Adjustments for REIT basis 2 — 81 — (1,469 ) — Company’s equity in net loss within continuing operations $ (66 ) $ (179 ) $ (277 ) $ (1,950 ) $ (292 ) 1. Includes CBRE Strategic Partners Asia and the Morristown JV. 2. Goodman UK JV amount includes write-down of $1,462 recorded on the Company’s outside basis during the six months ended June 30, 2018 related to its accumulated foreign currency translation adjustments recorded on the investment. The following are the statements of operations for the Company’s unconsolidated equity investments for the three months ended June 30, 2017 : Gramercy European Property Fund 1 Goodman Europe JV Gramercy European Property Fund 2 Total Strategic Office Partners Goodman UK JV Other 3 Revenues $ 5,323 $ 11,479 $ 16,802 $ 7,174 $ 293 $ 1,324 Operating expenses 945 2,802 3,747 2,316 225 399 Interest expense 614 1,798 2,412 2,055 — 700 Depreciation and amortization 2,024 5,322 7,346 2,852 261 333 Total expenses 3,583 9,922 13,505 7,223 486 1,432 Net income (loss) from operations 1,740 1,557 3,297 (49 ) (193 ) (108 ) Gain (loss) on derivatives — 1,049 1,049 (413 ) — — Provision for taxes (15 ) (424 ) (439 ) — (20 ) — Net income (loss) $ 1,725 $ 2,182 $ 3,907 $ (462 ) $ (213 ) $ (108 ) Company’s share in net income (loss) $ 88 $ 439 $ 527 $ (36 ) $ (171 ) $ 5 Adjustments for REIT basis 2 (37 ) — (37 ) — (40 ) — Company’s equity in net income (loss) within continuing operations $ 51 $ 439 $ 490 $ (36 ) $ (211 ) $ 5 1. As of and for the three months ended June 30, 2017 , the Company had a 5.1% direct interest in the Goodman Europe JV as well as an indirect interest in the remaining 94.9% interest that was held through the Company’s 14.2% interest in the Gramercy European Property Fund. For the three months ended June 30, 2017 , the Company’s equity in net income (loss) from the entities is based on these ownership interest percentages during the period. 2. Excludes the results of the Gramercy European Property Fund’s 94.9% interest in the Goodman Europe JV, as the Goodman Europe JV is separately presented. 3. Includes CBRE Strategic Partners Asia, the Philips JV, the Morristown JV, and European Fund Carry Co. The following are the statements of operations for the Company’s unconsolidated equity investments for the six months ended June 30, 2017 : Gramercy European Property Fund 1 Goodman Europe JV Gramercy European Property Fund 2 Total Strategic Office Partners Goodman UK JV Other 3 Revenues $ 10,278 $ 21,597 $ 31,875 $ 12,700 $ 588 $ (7 ) Operating expenses 1,867 5,753 7,620 3,790 527 975 Interest expense 1,286 3,272 4,558 3,565 — 1,341 Depreciation and amortization 4,045 9,795 13,840 5,355 636 666 Total expenses 7,198 18,820 26,018 12,710 1,163 2,982 Net income (loss) from operations 3,080 2,777 5,857 (10 ) (575 ) (2,989 ) Gain (loss) on derivatives — 2,270 2,270 (762 ) — — Provision for taxes (32 ) (278 ) (310 ) — (28 ) — Net income (loss) $ 3,048 $ 4,769 $ 7,817 $ (772 ) $ (603 ) $ (2,989 ) Company’s share in net income (loss) $ 155 $ 885 $ 1,040 $ (51 ) $ (483 ) $ (150 ) Adjustments for REIT basis 2 (73 ) — (73 ) — (129 ) — Company’s equity in net income (loss) within continuing operations $ 82 $ 885 $ 967 $ (51 ) $ (612 ) $ (150 ) 1. As of and for the six months ended June 30, 2017 , the Company had a 5.1% direct interest in the Goodman Europe JV as well as an indirect interest in the remaining 94.9% interest that was held through the Company’s 14.2% interest in the Gramercy European Property Fund. For the six months ended June 30, 2017 , the Company’s equity in net income (loss) from the entities is based on these ownership interest percentages during the period. 2. Excludes the results of the Gramercy European Property Fund’s 94.9% interest in the Goodman Europe JV, as the Goodman Europe JV is separately presented. 3. Includes CBRE Strategic Partners Asia, the Philips JV, the Morristown JV, and European Fund Carry Co.

Debt Obligations (Tables)

Debt Obligations (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Mortgage Notes Payable	The following is a summary of the Company’s secured financing arrangements as of June 30, 2018 and December 31, 2017 : Property Interest Rate 1 Maturity Date Outstanding Balance June 30, 2018 December 31, 2017 Philadelphia, PA 4.99% 1/1/2019 $ 11,743 $ 11,943 Bridgeview, IL 3.90% 5/1/2019 5,745 5,838 Spartanburg, SC 3.20% 6/1/2019 427 632 Charleston, SC 3.11% 8/1/2019 181 457 Lawrence, IN 5.02% 1/1/2020 19,730 20,061 Charlotte, NC 3.28% 1/1/2020 1,185 1,538 Hawthorne, CA 3.52% 8/1/2020 16,960 17,207 Charleston, SC 3.32% 10/1/2020 633 758 Charleston, SC 2.97% 10/1/2020 622 746 Charleston, SC 3.37% 10/1/2020 622 746 Charlotte, NC 3.38% 10/1/2020 540 647 Des Plaines, IL 5.54% 10/31/2020 2,344 2,385 Waco, TX 4.75% 12/19/2020 14,741 14,890 Deerfield, IL 3.71% 1/1/2021 10,263 10,447 Winston-Salem, NC 3.41% 6/1/2021 2,913 3,354 Winston-Salem, NC 3.42% 7/1/2021 971 1,114 Logistics Portfolio - Pool 1 2 4.27% 1/1/2022 37,603 38,107 CCC Portfolio 2 4.24% 10/6/2022 22,572 22,814 Logistics Portfolio - Pool 4 2 4.36% 12/5/2022 79,500 79,500 Romeoville, IL 3.80% 4/6/2023 24,724 24,951 Romeoville, IL 3 9.37% 4/6/2023 6,605 6,623 KIK USA Portfolio 2 4.31% 7/6/2023 7,001 7,154 Yuma, AZ 5.27% 12/6/2023 11,752 11,858 Allentown, PA 5.16% 1/6/2024 22,487 22,690 Spartanburg, SC 3.72% 2/1/2024 5,256 5,635 Natick, MA 5.21% 3/1/2024 31,027 31,224 Natick, MA 3 10.38% 3/1/2024 3,447 3,469 Maple Grove, MN 3.88% 5/6/2024 16,201 16,380 Curtis Bay, MD 4.31% 7/1/2024 13,500 13,500 Rialto, CA 3.91% 8/1/2024 54,344 54,741 Houston, TX 3.68% 9/1/2024 26,000 26,000 Durham, NC 4.02% 9/6/2024 3,597 3,631 Charleston, SC 3.80% 2/1/2025 5,658 6,001 Hackettstown, NJ 5.49% 3/6/2026 9,387 9,455 Hutchins, TX 5.41% 6/1/2029 20,955 21,578 Greenwood, IN 3.59% 6/15/2018 — 7,257 Greenfield, IN 3.63% 6/15/2018 — 5,865 Logistics Portfolio - Pool 3 3.96% 8/1/2018 — 43,302 Total mortgage notes payable $ 491,236 $ 554,498 Net deferred financing costs and net debt premium 7,979 9,023 Total mortgage notes payable, net $ 499,215 $ 563,521 1. Represents the interest rate as of June 30, 2018 that was recorded for financial reporting purposes, which reflects the effect of interest rate swaps and amortization of financing costs and fair market value premiums or discounts. 2. As of June 30, 2018 , there were three properties under the Logistics Portfolio - Pool 1 mortgage, five properties under the CCC Portfolio mortgage, six properties under the Logistics Portfolio - Pool 4 mortgage, and three properties under the KIK USA Portfolio mortgage. 3. Mortgage notes represent mezzanine financing at the properties.
Schedule of Line of Credit Facilities	The terms of the Company’s unsecured debt obligations and outstanding balances as of June 30, 2018 and December 31, 2017 are set forth in the table below: Stated Interest Rate Effective Interest Rate 1 Maturity Date Outstanding Balance June 30, 2018 December 31, 2017 2015 Revolving Credit Facility - USD tranche 3.08 % 3.08 % 1/8/2020 $ 405,000 $ 345,000 2015 Revolving Credit Facility - Multicurrency tranche 1.11 % 1.11 % 1/8/2020 36,773 12,162 3-Year Term Loan 3.23 % 2.33 % 1/8/2019 300,000 300,000 5-Year Term Loan 3.23 % 2.70 % 1/8/2021 750,000 750,000 7-Year Term Loan 3.08 % 3.00 % 1/9/2023 400,000 400,000 2015 Senior Unsecured Notes 4.97 % 5.07 % 12/17/2024 150,000 150,000 2016 Senior Unsecured Notes 3.89 % 4.00 % 12/15/2022 150,000 150,000 2016 Senior Unsecured Notes 4.26 % 4.38 % 12/15/2025 100,000 100,000 2016 Senior Unsecured Notes 4.32 % 4.43 % 12/15/2026 100,000 100,000 Total unsecured debt 2,391,773 2,307,162 Net deferred financing costs and net debt discount (4,680 ) (5,063 ) Total unsecured debt, net $ 2,387,093 $ 2,302,099 1. Represents the rate at which interest expense is recorded for financial reporting purposes as of June 30, 2018 , which reflects the effect of interest rate swaps and amortization of financing costs and fair market value premiums or discounts.
Schedule of Maturities of Long-term Debt	Combined aggregate principal maturities of the Company’s unsecured debt obligations and non-recourse mortgages, in addition to associated interest payments, as of June 30, 2018 are as follows: July 1 to December 31, 2018 2019 2020 2021 2022 Thereafter Above market interest Total 2015 Revolving Credit Facility $ — $ — $ 441,773 $ — $ — $ — $ — $ 441,773 Term Loans — 300,000 — 750,000 — 400,000 — 1,450,000 Mortgage Notes Payable 1 6,880 30,450 62,834 19,256 141,929 229,887 — 491,236 Senior Unsecured Notes — — — — 150,000 350,000 — 500,000 Interest Payments 2 54,009 104,625 89,976 58,015 53,868 64,822 3,299 428,614 Total $ 60,889 $ 435,075 $ 594,583 $ 827,271 $ 345,797 $ 1,044,709 $ 3,299 $ 3,311,623 1. Mortgage note payments reflect accelerated repayment dates, when applicable, pursuant to the related agreement. 2. Interest payments do not reflect the effect of interest rate swaps.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Carrying Value and Fair Value of Financial Instruments	The following table presents the carrying value in the financial statements and approximate fair value of assets and liabilities measured on a recurring and non-recurring basis at June 30, 2018 and December 31, 2017 : June 30, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value Financial assets: Interest rate swaps $ 35,212 $ 35,212 $ 19,668 $ 19,668 Retained CDO Bonds 6,792 6,792 5,527 5,527 Real estate investments 1 2,592 2,592 87,996 87,996 Investment in CBRE Strategic Partners Asia 2,062 2,062 2,820 2,820 Loan investments 2 33,169 28,872 22,154 21,362 Financial liabilities: Interest rate swaps $ — $ — $ 173 $ 173 Long-term debt: 2015 Revolving Credit Facility 2 441,773 441,823 357,162 357,369 3-Year Term Loan 2 300,000 300,066 300,000 300,091 5-Year Term Loan 2 750,000 750,573 750,000 750,678 7-Year Term Loan 2 398,330 400,006 398,152 400,010 Mortgage notes payable 2 499,215 502,870 563,521 573,826 Senior Unsecured Notes 2 496,990 494,455 496,785 513,229 1. Amounts represent two and seven real estate investments, respectively, that were impaired by the Company and held as of June 30, 2018 and December 31, 2017 . 2. Long-term debt instruments are classified as Level III due to the significance of unobservable inputs which are based upon management assumptions.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Assets and liabilities measured at fair value on a recurring and non-recurring basis are categorized as follows: At June 30, 2018 Total Level I Level II Level III Financial Assets: Retained CDO Bonds $ 6,792 $ — $ — $ 6,792 Real estate investments 2,592 — — 2,592 Investment in CBRE Strategic Partners Asia 2,062 — — 2,062 Interest rate swaps 35,212 — — 35,212 $ 46,658 $ — $ — $ 46,658 At December 31, 2017 Total Level I Level II Level III Financial Assets: Retained CDO Bonds $ 5,527 $ — $ — $ 5,527 Real estate investments 87,996 — — 87,996 Investment in CBRE Strategic Partners Asia 2,820 — — 2,820 Interest rate swaps 19,668 — — 19,668 $ 116,011 $ — $ — $ 116,011 Financial Liabilities: Interest rate swaps $ (173 ) $ — $ — $ (173 ) $ (173 ) $ — $ — $ (173 )
Fair Value, Assets and Liabilities Measured on Recurring Basis, Valuation Techniques	Quantitative information regarding the valuation techniques and the range of significant unobservable Level III inputs used to determine fair value measurements on a recurring basis as of June 30, 2018 are as follows: Financial Asset (Liability) Fair Value Valuation Technique Unobservable Inputs Range Non-investment grade, subordinate CDO bonds $ 6,792 Discounted cash flows Discount rate 19.0% Investment in CBRE Strategic Partners Asia 2,062 Discounted cash flows Discount rate 20.0% Interest rate swaps 35,212 Hypothetical derivative method Credit borrowing spread 110 to 175 basis points
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following rollforward table reconciles the beginning and ending balances of financial assets (liabilities) measured at fair value on a recurring basis using Level III inputs as of June 30, 2018 : Retained CDO Bonds Investment in CBRE Strategic Partners Asia Interest Rate Swaps Total Financial Assets (Liabilities) - Level III Balance at January 1, 2018 $ 5,527 $ 2,820 $ 19,495 $ 27,842 Amortization of discounts or premiums 646 — (35 ) 611 Adjustments to fair value: Termination of derivative instrument — — (11,288 ) (11,288 ) Unrealized gain on derivatives — — 27,040 27,040 Unrealized loss in other comprehensive income from fair value adjustment 619 — — 619 Total loss on fair value adjustments — (251 ) — (251 ) Distributions from financial assets — (507 ) — (507 ) Balance at June 30, 2018 $ 6,792 $ 2,062 $ 35,212 $ 44,066
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following rollforward table reconciles the beginning and ending balances of financial assets (liabilities) measured at fair value on a recurring basis using Level III inputs as of June 30, 2018 : Retained CDO Bonds Investment in CBRE Strategic Partners Asia Interest Rate Swaps Total Financial Assets (Liabilities) - Level III Balance at January 1, 2018 $ 5,527 $ 2,820 $ 19,495 $ 27,842 Amortization of discounts or premiums 646 — (35 ) 611 Adjustments to fair value: Termination of derivative instrument — — (11,288 ) (11,288 ) Unrealized gain on derivatives — — 27,040 27,040 Unrealized loss in other comprehensive income from fair value adjustment 619 — — 619 Total loss on fair value adjustments — (251 ) — (251 ) Distributions from financial assets — (507 ) — (507 ) Balance at June 30, 2018 $ 6,792 $ 2,062 $ 35,212 $ 44,066

Derivatives and Non-Derivativ30

Derivatives and Non-Derivative Hedging Instruments (Tables)	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The Company’s derivatives and hedging instruments as of June 30, 2018 are as follows: Benchmark Rate Notional Value Strike Rate Effective Date Expiration Date Fair Value Interest Rate Swap - Waco 1 mo. USD-LIBOR-BBA 14,741 USD 4.55% 12/19/2013 12/19/2020 $ 64 Interest Rate Swap - 3-Year Term Loan 1 mo. USD-LIBOR-BBA 100,000 USD 1.22% 12/19/2016 12/17/2018 472 Interest Rate Swap - 3-Year Term Loan 1 mo. USD-LIBOR-BBA 100,000 USD 1.23% 12/19/2016 12/17/2018 470 Interest Rate Swap - 3-Year Term Loan 1 mo. USD-LIBOR-BBA 100,000 USD 1.24% 12/19/2016 12/17/2018 465 Interest Rate Swap - 5-Year Term Loan 1 mo. USD-LIBOR-BBA 750,000 USD 1.60% 12/17/2015 12/17/2020 19,539 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 175,000 USD 1.82% 12/17/2015 1/9/2023 6,853 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 60,000 USD 1.95% 10/13/2017 1/9/2023 2,025 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 40,000 USD 2.01% 10/13/2017 1/9/2023 1,243 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 39,500 USD 1.96% 10/13/2017 1/9/2023 1,298 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 31,500 USD 1.96% 10/13/2017 1/9/2023 1,038 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 31,500 USD 2.00% 10/13/2017 1/9/2023 991 Interest Rate Swap - 7-Year Term Loan 1 mo. USD-LIBOR-BBA 22,500 USD 1.95% 10/13/2017 1/9/2023 754 Net Investment Hedge in GBP-denominated investments USD-GBP exchange rate 9,000 GBP N/A 7/15/2016 N/A — Net Investment Hedge in EUR-denominated investments USD-EUR exchange rate 21,300 EUR N/A 3/8/2018 N/A — Total hedging instruments $ 35,212
Gain (Loss) Recognized On Interest Rate Swaps	The table below details the location in the financial statements of the gain or loss recognized on the interest rate swaps designated as cash flow hedges for the three and six months ended June 30, 2018 and 2017 : Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Accumulated other comprehensive income: Gain recognized in accumulated other comprehensive income 1 $ 4,990 $ — $ 27,143 $ — Interest expense: Loss reclassified from accumulated other comprehensive income into interest expense 1 $ 271 $ 271 $ 539 $ 539 Gain recognized in interest expense (ineffective portion) 2 — — — 46 Total recognized in interest expense on statements of operations $ 271 $ 271 $ 539 $ 585 Gain on derivative instruments: Gain reclassified from other comprehensive income into gain on derivative instruments 3 $ 14,970 $ — $ 14,970 $ — 1. Periods prior to January 1, 2018, when the Company adopted ASU 2017-12, include only the effective portion and periods subsequent to January 1, 2018 include both the effective and ineffective portions as the two amounts are no longer separately measured and reported. The six months ended June 30, 2018 includes $103 related to the adoption of ASU 2017-02. 2. Represents the ineffective portion and pertains only to periods prior to January 1, 2018, when the Company adopted ASU 2017-12. 3. Amounts represent gain recognized during the three and six months ended June 30, 2018 related to the Company’s termination of its forward starting swap in June 2018.

Shareholders' Equity (Deficit31

Shareholders' Equity (Deficit) of the Company (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Dividends	During the six months ended June 30, 2018 , the Company’s common dividends were as follows: Quarter Ended Record Date Payment Date Common dividend per share March 31, 2018 3/30/2018 4/16/2018 $ 0.375 June 30, 2018 6/29/2018 7/16/2018 $ 0.375
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	Earnings per share for the three and six months ended June 30, 2018 and 2017 are computed as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator – Income (loss): Net income (loss) from continuing operations $ 20,754 $ 5,985 $ 32,363 $ (2,087 ) Net loss from discontinued operations — (28 ) — (52 ) Net income (loss) before net gain on disposals 20,754 5,957 32,363 (2,139 ) Net gain on disposals 4,523 2,002 20,778 19,379 Net income 25,277 7,959 53,141 17,240 Less: Net (income) loss attributable to noncontrolling interest (845 ) 113 (1,647 ) (41 ) Less: Nonforfeitable dividends allocated to participating shareholders (206 ) (337 ) (409 ) (635 ) Less: Preferred share dividends (1,558 ) (1,558 ) (3,117 ) (3,117 ) Net income available to common shares outstanding $ 22,668 $ 6,177 $ 47,968 $ 13,447 Denominator – Weighted average shares: Basic weighted average shares outstanding 160,420,278 148,542,916 160,414,240 144,746,251 Effect of dilutive securities: Unvested non-participating share-based payment awards — 86,452 — 79,552 Options 13,073 19,196 11,051 14,471 Exchangeable Senior Notes — 1,265,879 — 1,125,662 Diluted weighted average shares outstanding 160,433,351 149,914,443 160,425,291 145,965,936 The Operating Partnership's earnings per unit for the three and six months ended June 30, 2018 and 2017 are computed as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator – Income (loss): Net income (loss) from continuing operations $ 20,754 $ 5,985 $ 32,363 $ (2,087 ) Net loss from discontinued operations — (28 ) — (52 ) Net income (loss) before net gain on disposals 20,754 5,957 32,363 (2,139 ) Net gain on disposals 4,523 2,002 20,778 19,379 Net income 25,277 7,959 53,141 17,240 Less: Net loss attributable to noncontrolling interest in other partnerships — 137 — 17 Less: Nonforfeitable dividends allocated to participating unitholders (206 ) (337 ) (409 ) (635 ) Less: Preferred unit distributions (1,558 ) (1,558 ) (3,117 ) (3,117 ) Net income available to common units outstanding $ 23,513 $ 6,201 $ 49,615 $ 13,505 Denominator – Weighted average units: Basic weighted average units outstanding 166,355,043 149,103,359 165,904,457 145,336,798 Effect of dilutive securities: Unvested non-participating share-based payment awards — 86,452 — 79,552 Options 13,073 19,196 11,051 14,471 Exchangeable Senior Notes — 1,265,879 — 1,125,662 Diluted weighted average units outstanding 166,368,116 150,474,886 165,915,508 146,556,483
Schedule of Accumulated Other Comprehensive Income (Loss)	Accumulated other comprehensive income as of June 30, 2018 and December 31, 2017 is composed of the following: June 30, 2018 December 31, 2017 Net unrealized gain on derivative securities $ 42,670 $ 15,630 Net unrealized gain on debt instruments 1,036 417 Foreign currency translation adjustments: Net gain on non-derivative net investment hedges 1 865 297 Other foreign currency translation adjustments (6,966 ) (5,734 ) Reclassification of swap gain (loss) into interest expense (8,583 ) 2,166 Cumulative effect of accounting change 103 — Total accumulated other comprehensive income $ 29,125 $ 12,776 1. The foreign currency translation adjustment associated with the Company’s non-derivative net investment hedge related to its European investments is included in other comprehensive income. The balance reflects write-offs of $1,851 on the Company’s non-derivative net investment hedge during the year ended December 31, 2017 .

Partners' Capital of the Oper32

Partners' Capital of the Operating Partnership (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	Earnings per share for the three and six months ended June 30, 2018 and 2017 are computed as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator – Income (loss): Net income (loss) from continuing operations $ 20,754 $ 5,985 $ 32,363 $ (2,087 ) Net loss from discontinued operations — (28 ) — (52 ) Net income (loss) before net gain on disposals 20,754 5,957 32,363 (2,139 ) Net gain on disposals 4,523 2,002 20,778 19,379 Net income 25,277 7,959 53,141 17,240 Less: Net (income) loss attributable to noncontrolling interest (845 ) 113 (1,647 ) (41 ) Less: Nonforfeitable dividends allocated to participating shareholders (206 ) (337 ) (409 ) (635 ) Less: Preferred share dividends (1,558 ) (1,558 ) (3,117 ) (3,117 ) Net income available to common shares outstanding $ 22,668 $ 6,177 $ 47,968 $ 13,447 Denominator – Weighted average shares: Basic weighted average shares outstanding 160,420,278 148,542,916 160,414,240 144,746,251 Effect of dilutive securities: Unvested non-participating share-based payment awards — 86,452 — 79,552 Options 13,073 19,196 11,051 14,471 Exchangeable Senior Notes — 1,265,879 — 1,125,662 Diluted weighted average shares outstanding 160,433,351 149,914,443 160,425,291 145,965,936 The Operating Partnership's earnings per unit for the three and six months ended June 30, 2018 and 2017 are computed as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator – Income (loss): Net income (loss) from continuing operations $ 20,754 $ 5,985 $ 32,363 $ (2,087 ) Net loss from discontinued operations — (28 ) — (52 ) Net income (loss) before net gain on disposals 20,754 5,957 32,363 (2,139 ) Net gain on disposals 4,523 2,002 20,778 19,379 Net income 25,277 7,959 53,141 17,240 Less: Net loss attributable to noncontrolling interest in other partnerships — 137 — 17 Less: Nonforfeitable dividends allocated to participating unitholders (206 ) (337 ) (409 ) (635 ) Less: Preferred unit distributions (1,558 ) (1,558 ) (3,117 ) (3,117 ) Net income available to common units outstanding $ 23,513 $ 6,201 $ 49,615 $ 13,505 Denominator – Weighted average units: Basic weighted average units outstanding 166,355,043 149,103,359 165,904,457 145,336,798 Effect of dilutive securities: Unvested non-participating share-based payment awards — 86,452 — 79,552 Options 13,073 19,196 11,051 14,471 Exchangeable Senior Notes — 1,265,879 — 1,125,662 Diluted weighted average units outstanding 166,368,116 150,474,886 165,915,508 146,556,483

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	6 Months Ended
	Jun. 30, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interest in the Operating Partnership	Below is the rollforward of the activity relating to the noncontrolling interests in the Operating Partnership as of June 30, 2018 : Noncontrolling Interest Balance at January 1, 2018 $ 113,530 Issuance of noncontrolling interests in the Operating Partnership 37,558 Redemption of noncontrolling interests in the Operating Partnership (130 ) Net income attribution 1,647 Fair value adjustments 7,448 Dividends (3,760 ) Balance at June 30, 2018 $ 156,293

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments	Future minimum rental payments to be made by the Company under these non-cancelable ground leases, excluding increases resulting from increases in the consumer price index, are as follows: July 1 to December 31, 2018 2019 2020 2021 2022 Thereafter Total Ground Leases - Operating $ 1,266 $ 2,593 $ 2,596 $ 2,567 $ 2,598 $ 73,175 $ 84,795 Ground Leases - Capital — — — — — 329 329 Total $ 1,266 $ 2,593 $ 2,596 $ 2,567 $ 2,598 $ 73,504 $ 85,124

Supplemental Cash Flow Inform35

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Schedule of Supplemental Cash Flow Activities	The following table represents supplemental cash flow disclosures for the six months ended June 30, 2018 and 2017 : Six Months Ended June 30, 2018 2017 Supplemental cash flow disclosures: Interest paid $ 50,194 $ 44,441 Income taxes paid 218 296 Proceeds from 1031 exchanges from sale of real estate 5 170,210 Use of funds from 1031 exchanges for acquisitions of real estate (5 ) (140,987 ) Non-cash activity: Fair value adjustment to noncontrolling interest in the Operating Partnership $ 7,448 $ 576 Debt assumed in acquisition of real estate — 3,680 Debt transferred in disposition of real estate — (10,456 ) Non-cash acquisition of consolidated VIE — 24,930 Dividend reinvestment plan proceeds 81 103 Redemption of units of noncontrolling interest in the Operating Partnership for common shares (130 ) (2,697 ) Contributions to unconsolidated equity investments for units of noncontrolling interests in the operating partnership 37,558 —

Business and Organization (Narr

Business and Organization (Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)ft²buildingPropertyimpaired_property	Jun. 30, 2017USD ($)ft²Propertyimpaired_property	Jun. 30, 2018USD ($)ft²buildingProperty	Jun. 30, 2018USD ($)ft²buildingProperty$ / shares	Jun. 30, 2018USD ($)ft²buildingProperty	Jun. 30, 2018USD ($)ft²buildingProperty	Jun. 30, 2018USD ($)ft²buildingPropertyimpaired_property	Jun. 30, 2018USD ($)ft²buildingPropertyland_parcel	Jun. 30, 2018USD ($)ft²buildingProperty	Jun. 30, 2017USD ($)	Jun. 30, 2017Property	Jun. 30, 2017impaired_property	Jun. 30, 2017ft²	May 06, 2018USD ($)$ / shares	Dec. 31, 2017Property
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of properties | Property	361		361	361	361	361	361	361	361						371
Total purchase price of all acquisitions	$ 22,140	$ 177,740	$ 32,690							$ 302,412
Number of properties | impaired_property	2	3
Rentable square feet | ft²	343,966	1,739,881							1,890,057				2,227,753
Gross proceeds	$ 19,971	$ 183,302	$ 130,983							$ 234,985
Wholly Owned Properties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of properties | building	355		355	355	355	355	355	355	355
Area of real estate property | ft²	81,134,150		81,134,150	81,134,150	81,134,150	81,134,150	81,134,150	81,134,150	81,134,150
Occupancy rate	96.70%		96.70%	96.70%	96.70%	96.70%	96.70%	96.70%	96.70%
Unconsolidated Properties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of properties | building	33		33	33	33	33	33	33	33
GPT Operating Partnership LP
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Ownership percentage by noncontrolling owners	3.58%		3.58%	3.58%	3.58%	3.58%	3.58%	3.58%	3.58%
Gramercy Asset Management | Commercial Lease Properties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Commercial real estate assets	$ 2,364,000		$ 2,364,000	$ 2,364,000	$ 2,364,000	$ 2,364,000	$ 2,364,000	$ 2,364,000	$ 2,364,000
Europe | Gramercy Asset Management | Commercial Lease Properties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Commercial real estate assets	$ 1,617,000		$ 1,617,000	$ 1,617,000	$ 1,617,000	$ 1,617,000	$ 1,617,000	$ 1,617,000	$ 1,617,000
CBRE Strategic Partners Asia
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of properties | Property	1		1	1	1	1	1	1	1
Operating Properties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of operating properties | Property	2	10				3					17
Rentable square feet of operating properties | ft²	388,466	2,493,043							550,522				4,750,354
Development Property
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of Acquisitions | Property						1
Rentable square feet of operating properties | ft²									126,722
Disposed by Sale
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of properties	9	10				14	2	1			17	3
Blackstone Group LP
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Share price (in usd per share) | $ / shares														$ 27.50
Fee additional to acquisition price per share on per diem basis (in usd per share) | $ / shares				$ 0.004
Termination fee to parent														$ 138,000
Termination fee to the Company														$ 414,000
7.125% Series A Preferred Stock
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Dividend rate on preferred stock					7.125%
Distribution on preferred stock (in usd per share) | $ / shares														$ 25

Real Estate Investments (Schedu

Real Estate Investments (Schedule of Real Estate Investments) (Details) $ in Thousands	Jun. 30, 2018USD ($)ft²Property	Dec. 31, 2017USD ($)ft²Property
Real Estate [Line Items]
Rentable area (in sqft) | ft²	82,787,450	83,776,085
Number of properties | Property	361	371
Operating properties	$ 5,828,172	$ 5,857,906
Land parcels	7,075	7,075
Less: accumulated depreciation	(410,020)	(333,151)
Total operating properties and land parcels	5,425,227	5,531,830
Development properties	22,625	22,843
Total real estate investments, net	$ 5,447,852	$ 5,554,673
Operating parcels
Real Estate [Line Items]
Rentable area (in sqft) | ft²	81,134,150	82,146,063
Number of properties | Property	353	363
Land parcels
Real Estate [Line Items]
Number of properties | Property	2	2
Development properties
Real Estate [Line Items]
Rentable area (in sqft) | ft²	1,653,300	1,630,022
Number of properties | Property	6	6

Real Estate Investments (Summar

Real Estate Investments (Summary of Asset Acquisitions) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)ft²Property	Jun. 30, 2017USD ($)ft²Property	Jun. 30, 2018USD ($)ft²Property	Jun. 30, 2017USD ($)ft²Property
Real Estate [Line Items]
Total purchase price of all acquisitions | $	$ 22,140	$ 177,740	$ 32,690	$ 302,412
Operating Properties
Real Estate [Line Items]
Number of operating properties | Property	2	10	3	17
Rentable square feet of operating properties | ft²	388,466	2,493,043	550,522	4,750,354
Land Parcels
Real Estate [Line Items]
Number of operating properties | Property	0	2	0	2
Development Property
Real Estate [Line Items]
Rentable square feet of operating properties | ft²			126,722

Significant Accounting Polici39

Significant Accounting Policies (Narrative) (Details)	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2017USD ($)Propertyentity	Jun. 30, 2018USD ($)Propertycollateralized_debt_obligationsentity	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Propertycollateralized_debt_obligationsentity	Jun. 30, 2017USD ($)	Mar. 31, 2017Property	Dec. 31, 2016USD ($)
Accounting Policies [Line Items]
Net cash provided by operating activities				$ 148,283,000	$ 126,062,000
Net cash used in investing activities				(28,709,000)	(130,655,000)
Net cash provided by financing activities				$ (90,660,000)	128,073,000
Number of consolidated VIEs | entity	5	5		5
Number of unconsolidated variable interest entities | entity	2	2		2
Number of investments held | collateralized_debt_obligations		2		2
Allowance for doubtful accounts receivable	$ 638,000	$ 692,000		$ 692,000
Accumulated deficit	$ (1,369,872,000)	$ (1,442,153,000)		$ (1,442,153,000)
Number of properties | Property	371	361		361
Impairment of goodwill				$ 3,293,000
Available-for-sale Securities
Accounting Policies [Line Items]
Retained collateralized debt obligations (CDOs) bonds, other-than-temporary impairment		$ 0	$ 0	$ 0
Lakemont Development Investment
Accounting Policies [Line Items]
Number of Acquisitions | Property	4
Economic Ownership		95.00%		95.00%
Ownership percentage by noncontrolling owners		5.00%		5.00%
Carrying amount of VIE	$ 4,584,000	$ 4,765,000		$ 4,765,000
Gramercy Europe Asset | Canada
Accounting Policies [Line Items]
Number of properties | Property						2
Retained CDO Bonds
Accounting Policies [Line Items]
Retained CDO Bonds carrying value	5,527,000	6,792,000		6,792,000
Gramercy Europe Limited
Accounting Policies [Line Items]
Goodwill	3,272,000	0		$ 0			$ 3,802,000
Building
Accounting Policies [Line Items]
Property, plant and equipment, useful life				40 years
Building Equipment and Fixtures | Minimum
Accounting Policies [Line Items]
Property, plant and equipment, useful life				5 years
Building Equipment and Fixtures | Maximum
Accounting Policies [Line Items]
Property, plant and equipment, useful life				10 years
ASU 2016-18
Accounting Policies [Line Items]
Net cash provided by operating activities					19,000
Net cash used in investing activities					26,523,000
Net cash provided by financing activities					$ 880,000
ASU 2014-09
Accounting Policies [Line Items]
Accumulated deficit	663,000
Construction Loans
Accounting Policies [Line Items]
Borrowing capacity		250,000,000		$ 250,000,000
Net amount	$ 22,154,000	$ 33,169,000		$ 33,169,000
Basis spread on rate				11.36%

Real Estate Investments (Summ40

Real Estate Investments (Summary of Dispositions) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)ft²Propertyimpaired_property	Jun. 30, 2017USD ($)ft²Propertyimpaired_property	Jun. 30, 2018USD ($)	Jun. 30, 2018Property	Jun. 30, 2018impaired_property	Jun. 30, 2018land_parcel	Jun. 30, 2018ft²	Jun. 30, 2017USD ($)	Jun. 30, 2017Property	Jun. 30, 2017impaired_property	Jun. 30, 2017ft²
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties | impaired_property	2	3
Rentable square feet | ft²	343,966	1,739,881					1,890,057				2,227,753
Gross proceeds	$ 19,971	$ 183,302	$ 130,983					$ 234,985
Impairment of real estate investments related to asset dispositions during the period	0	528	0					13,299
Net gain on disposals	4,523	2,002	20,778					19,379
Impairment losses	$ (4,601)	$ (5,580)	(4,601)					(18,351)
Disposed by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties	9	10		14	2	1			17	3
Impairment losses	$ (1,308)	$ (5,052)	$ (1,308)					$ (5,052)

Significant Accounting Polici41

Significant Accounting Policies (Components of Cash, Cash Equivalents and Restricted Cash) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 59,741	$ 30,231	$ 163,509
Restricted cash	12,026	12,723	40,326
Total cash, cash equivalents, and restricted cash	$ 71,767	$ 42,954	$ 203,835	$ 80,433

Real Estate Investments (Narrat

Real Estate Investments (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)ft²Propertyimpaired_property	Jun. 30, 2017USD ($)ft²impaired_property	Jun. 30, 2018USD ($)ft²Property	Jun. 30, 2017USD ($)ft²	Dec. 31, 2017USD ($)Property
Real Estate [Line Items]
Amortization of Intangible Assets	$ 22,983	$ 24,167	$ 49,142	$ 48,339
Real estate acquisitions	21,691		31,888
Intangible assets acquisitions	$ 2,060		$ 2,695
Number of properties | impaired_property	2	3
Rentable square feet | ft²	343,966	1,739,881	1,890,057	2,227,753
Net gain on disposals	$ 4,523	$ 2,002	$ 20,778	$ 19,379
Impairment losses	(4,601)	(5,580)	(4,601)	(18,351)
Assets held for sale, net	0		0		$ 402
Amortization of market lease intangible assets and liabilities	$ 1,433	$ 4,756	$ 1,927	$ 5,377
Assets Held-for-sale
Real Estate [Line Items]
Number of properties held-for-sale | Property	0		0		1
Net asset value	$ 402		$ 402
Development Property
Real Estate [Line Items]
Number of Acquisitions | Property			1
Rentable square feet of operating properties | ft²			126,722

Significant Accounting Polici43

Significant Accounting Policies (Schedule of Retained Collateralized Debt Obligation Bonds) (Details) - Available-for-sale Securities $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)security	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)security
Debt Securities, Available-for-sale [Line Items]
Number of Securities | security	6		6
Face Value	$ 332,360		$ 332,360
Amortized Cost	5,756		5,756
Gross Unrealized Gain			1,036
Other-than-temporary impairment	0	$ 0	0
Fair Value	$ 6,792		$ 6,792
Weighted Average Expected Life			9 months 18 days

Real Estate Investments (Summ44

Real Estate Investments (Summary of Intangibles) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Intangible assets:
Total intangible assets	$ 537,824	$ 598,559
Finite-lived intangible assets, accumulated amortization	265,990	220,473
Intangible liabilities:
Total intangible liabilities	$ 148,661	166,491
In-place leases
Real Estate [Line Items]
Weighted average amortization period (years)	9 years 4 months 24 days
Intangible assets:
Total intangible assets	$ 490,350	545,782
Finite-lived intangible assets, accumulated amortization	$ 236,602	194,836
Above-market leases
Real Estate [Line Items]
Weighted average amortization period (years)	7 years 2 months 12 days
Intangible assets:
Total intangible assets	$ 41,700	46,713
Finite-lived intangible assets, accumulated amortization	$ 28,930	25,229
Below-market ground rent
Real Estate [Line Items]
Weighted average amortization period (years)	17 years 3 months 19 days
Intangible assets:
Total intangible assets	$ 5,774	6,064
Finite-lived intangible assets, accumulated amortization	$ 458	408
Below-market leases
Real Estate [Line Items]
Weighted average amortization period (years)	39 years 4 months 24 days
Intangible liabilities:
Total intangible liabilities	$ 141,929	159,652
Finite-lived intangible liabilities, accumulated amortization	$ 32,733	28,516
Above-market ground rent
Real Estate [Line Items]
Weighted average amortization period (years)	31 years 9 months 18 days
Intangible liabilities:
Total intangible liabilities	$ 6,732	6,839
Finite-lived intangible liabilities, accumulated amortization	569	462
Assets Held-for-sale
Intangible assets:
Finite-lived intangible assets, accumulated amortization	0	0
Intangible liabilities:
Finite-lived intangible liabilities, accumulated amortization	$ 0	$ 0

Real Estate Investments (Sche45

Real Estate Investments (Schedule of Finite-Lived Intangible Assets, Future Amortization Expense) (Details) $ in Thousands	Jun. 30, 2018USD ($)
Depreciation and amortization expense
July 1 to December 31, 2018	$ 44,977
2,019	81,899
2,020	70,915
2,021	60,426
2,022	47,619
Rental revenue increase
July 1 to December 31, 2018	(3,271)
2,019	(2,854)
2,020	(3,559)
2,021	(3,450)
2,022	$ (5,467)

Unconsolidated Equity Investm46

Unconsolidated Equity Investments (Narrative) (Details) € in Thousands, $ in Thousands	Jun. 30, 2016	Nov. 30, 2017USD ($)Property	Jun. 30, 2018USD ($)Property	Jun. 30, 2018EUR (€)Property	Jun. 30, 2018USD ($)Property	Jun. 30, 2018EUR (€)Property	Dec. 31, 2017USD ($)Property	Jun. 30, 2018EUR (€)Property	Oct. 31, 2017USD ($)	Oct. 31, 2017EUR (€)	Jul. 31, 2017
Investments in and Advances to Affiliates [Line Items]
Number of properties | Property			361		361		371	361
Investment in unconsolidated equity investment			$ 147,282		$ 147,282		$ 70,214
Contributions to unconsolidated equity investments					81,356
Commitment amount			$ 40,265		$ 40,265
Gramercy European Property Fund
Investments in and Advances to Affiliates [Line Items]
Ownership %							14.20%
Goodman Europe JV
Investments in and Advances to Affiliates [Line Items]
Ownership %							5.10%				5.10%
Gramercy European Property Fund III
Investments in and Advances to Affiliates [Line Items]
Ownership %			25.00%		25.00%			25.00%
Commitment amount			$ 400,000		$ 400,000
Cash contributions to equity method investment			2,950		2,950
Investment in unconsolidated equity investment			32,427		32,427
Gramercy European Property Fund III | Parent Company
Investments in and Advances to Affiliates [Line Items]
Commitment amount			$ 100,000		$ 100,000
Strategic Office Partners
Investments in and Advances to Affiliates [Line Items]
Ownership %			51.00%		51.00%			51.00%
Contributions to unconsolidated equity investments					$ 61,304
Commitment amount			$ 110,000		$ 110,000
Number of Acquisitions | Property		6	2	2	4	4	6
Partnership unit contributions to investment		$ 80,000	$ 12,416		$ 37,557
Cash contributions to equity method investment		$ 30,000	14,435		$ 15,565
Duke JV
Investments in and Advances to Affiliates [Line Items]
Ownership interest transferred	100.00%
E-Commerce JV
Investments in and Advances to Affiliates [Line Items]
Aggregate cost									$ 310,643	€ 262,622
Number of Acquisitions | Property					11	11
Investment in unconsolidated equity investment			28,186		$ 28,186			€ 23,478
Payments to investments			25,170	€ 20,964	22,710	€ 18,987
E-Commerce JV | Parent Company
Investments in and Advances to Affiliates [Line Items]
Aggregate cost			$ 61,730		$ 61,730			€ 52,187
Gramercy European Property Fund | Goodman Europe JV
Investments in and Advances to Affiliates [Line Items]
Ownership %							94.90%
Unconsolidated Equity Method Investments
Investments in and Advances to Affiliates [Line Items]
Number of properties | Property			34		34		17	34
Investment in unconsolidated equity investment			$ 147,282		$ 147,282		$ 70,214
Unconsolidated Equity Method Investments | Gramercy European Property Fund III
Investments in and Advances to Affiliates [Line Items]
Number of properties | Property			14		14		13	14
Investment in unconsolidated equity investment			$ 31,512		$ 31,512		$ 28,243
Voting Interest %			25.00%		25.00%			25.00%
Unconsolidated Equity Method Investments | Goodman UK JV
Investments in and Advances to Affiliates [Line Items]
Number of properties | Property			1		1		1	1
Ownership %			80.00%		80.00%			80.00%
Investment in unconsolidated equity investment			$ 13,480		$ 13,480		$ 15,768
Voting Interest %			50.00%		50.00%			50.00%
Unconsolidated Equity Method Investments | Strategic Office Partners
Investments in and Advances to Affiliates [Line Items]
Number of properties | Property			4		4		0	4
Investment in unconsolidated equity investment			$ 70,475		$ 70,475		$ 17,798
Voting Interest %			50.00%		50.00%			50.00%
Unconsolidated Equity Method Investments | E-Commerce JV
Investments in and Advances to Affiliates [Line Items]
Number of properties | Property			13		13		0	13
Ownership %			19.90%		19.90%			19.90%
Investment in unconsolidated equity investment			$ 27,045		$ 27,045		$ 2,949
Voting Interest %			50.00%		50.00%			50.00%

Unconsolidated Equity Investm47

Unconsolidated Equity Investments (Summary of Unconsolidated Equity Investments) (Details) $ in Thousands	Jun. 30, 2018USD ($)Property	Dec. 31, 2017USD ($)Property	Jul. 31, 2017
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated equity investment	$ 147,282	$ 70,214
Number of properties | Property	361	371
Strategic Office Partners
Schedule of Equity Method Investments [Line Items]
Ownership %	51.00%
Basis difference	$ (8,100)
Gramercy European Property Fund
Schedule of Equity Method Investments [Line Items]
Ownership %		14.20%
Goodman Europe JV
Schedule of Equity Method Investments [Line Items]
Ownership %		5.10%	5.10%
Goodman Europe JV | Gramercy European Property Fund
Schedule of Equity Method Investments [Line Items]
Ownership %		94.90%
Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Ownership %	25.00%
Goodman UK JV
Schedule of Equity Method Investments [Line Items]
Basis difference	$ 431	$ 1,943
Unconsolidated Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated equity investment	$ 147,282	$ 70,214
Number of properties | Property	34	17
Unconsolidated Equity Method Investments | Strategic Office Partners
Schedule of Equity Method Investments [Line Items]
Voting Interest %	50.00%
Investment in unconsolidated equity investment	$ 70,475	$ 17,798
Number of properties | Property	4	0
Unconsolidated Equity Method Investments | Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Voting Interest %	25.00%
Investment in unconsolidated equity investment	$ 31,512	$ 28,243
Number of properties | Property	14	13
Unconsolidated Equity Method Investments | Goodman UK JV
Schedule of Equity Method Investments [Line Items]
Ownership %	80.00%
Voting Interest %	50.00%
Investment in unconsolidated equity investment	$ 13,480	$ 15,768
Number of properties | Property	1	1
Unconsolidated Equity Method Investments | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Ownership %	19.90%
Voting Interest %	50.00%
Investment in unconsolidated equity investment	$ 27,045	$ 2,949
Number of properties | Property	13	0
Unconsolidated Equity Method Investments | Other
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated equity investment	$ 4,770	$ 5,456
Number of properties | Property	2	3
Minimum | Unconsolidated Equity Method Investments | Other
Schedule of Equity Method Investments [Line Items]
Ownership %	5.10%
Voting Interest %	5.10%
Maximum | Unconsolidated Equity Method Investments | Other
Schedule of Equity Method Investments [Line Items]
Ownership %	50.00%
Voting Interest %	50.00%

Unconsolidated Equity Investm48

Unconsolidated Equity Investments (Rollforward of Unconsolidated Equity Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]
Beginning balance			$ 70,214
Contributions to unconsolidated equity investments			81,356
Equity in net loss of unconsolidated equity investments, including adjustments for basis differences	$ (1,838)	$ 248	(2,764)	$ 154
Other comprehensive loss of unconsolidated equity investments			(1,632)
Distributions from unconsolidated equity investments			(555)
Cumulative effect of accounting change			663
Ending Balance	$ 147,282		$ 147,282

Unconsolidated Equity Investm49

Unconsolidated Equity Investments (Combined Balance Sheets for the Company's Joint Ventures) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jul. 31, 2017
Strategic Office Partners
Liabilities and members' equity:
Ownership %	51.00%
Gramercy European Property Fund
Liabilities and members' equity:
Ownership %		14.20%
Goodman Europe JV
Liabilities and members' equity:
Ownership %		5.10%	5.10%
Goodman Europe JV | Gramercy European Property Fund
Liabilities and members' equity:
Ownership %		94.90%
Gramercy European Property Fund III
Liabilities and members' equity:
Ownership %	25.00%
Corporate Joint Venture | Strategic Office Partners
Assets:
Real estate assets, net	$ 302,636	$ 0
Other assets	62,200	35,727
Total assets	364,836	35,727
Liabilities and members' equity:
Mortgage notes payable	216,863	0
Other liabilities	9,786	830
Total liabilities	226,649	830
Company's equity	70,475	17,798
Other members' equity	67,712	17,099
Liabilities and members' equity	364,836	35,727
Corporate Joint Venture | Gramercy European Property Fund
Assets:
Real estate assets, net	314,022
Other assets	68,677
Total assets	382,699
Liabilities and members' equity:
Mortgage notes payable	238,339
Other liabilities	8,253
Total liabilities	246,592
Company's equity	27,045
Other members' equity	109,062
Liabilities and members' equity	382,699
Corporate Joint Venture | Gramercy European Property Fund III
Assets:
Real estate assets, net	277,863	265,014
Other assets	88,048	78,243
Total assets	365,911	343,257
Liabilities and members' equity:
Mortgage notes payable	226,427	213,205
Other liabilities	14,009	15,002
Total liabilities	240,436	228,207
Company's equity	31,512	28,243
Other members' equity	93,963	86,807
Liabilities and members' equity	365,911	343,257
Corporate Joint Venture | Goodman UK JV
Assets:
Real estate assets, net	16,122	18,633
Other assets	921	1,473
Total assets	17,043	20,106
Liabilities and members' equity:
Mortgage notes payable	0	0
Other liabilities	0	203
Total liabilities	0	203
Company's equity	13,480	15,768
Other members' equity	3,563	4,135
Liabilities and members' equity	17,043	20,106
Corporate Joint Venture | Other
Assets:
Real estate assets, net	60,361	107,949
Other assets	15,628	34,022
Total assets	75,989	141,971
Liabilities and members' equity:
Mortgage notes payable	0	38,662
Other liabilities	15,793	19,329
Total liabilities	15,793	57,991
Company's equity	4,770	8,405
Other members' equity	55,426	75,575
Liabilities and members' equity	$ 75,989	$ 141,971

Unconsolidated Equity Investm50

Unconsolidated Equity Investments (Real Estate Assets Subject to Mortgages) (Details) $ in Thousands	Jun. 30, 2018USD ($)Property	Dec. 31, 2017USD ($)
Schedule of Equity Method Investments [Line Items]
Percentage of face amount of debt presented	100.00%
Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Economic Ownership	25.00%
Strategic Office Partners
Schedule of Equity Method Investments [Line Items]
Economic Ownership	51.00%
Wholly Owned Properties | Gramercy European Property Fund III - Bridge Facility | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Economic Ownership	19.90%
Wholly Owned Properties | Strategic Office Partners Portfolio Facility One | Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Economic Ownership	25.00%
Number of real estate properties pledged under debt | Property	10
Wholly Owned Properties | Strategic Office Partners Portfolio Facility Two | Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Economic Ownership	25.00%
Wholly Owned Properties | E-Commerce JV Portfolio Facility | Strategic Office Partners
Schedule of Equity Method Investments [Line Items]
Economic Ownership	51.00%
Wholly Owned Properties | Gramercy European Property Fund III Facility 1 | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Economic Ownership	19.90%
Number of real estate properties pledged under debt | Property	3
Wholly Owned Properties | Solingen, Germany | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Economic Ownership	19.90%
Wholly Owned Properties | Gramercy European Property Fund III Facility 2 | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Economic Ownership	19.90%
Wholly Owned Properties | Offenau, Germany | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Economic Ownership	19.90%
Wholly Owned Properties | Henderson, NV | Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Economic Ownership	25.00%
Mortgages
Schedule of Equity Method Investments [Line Items]
Total mortgage notes payable, net	$ 491,236
Mortgages | Wholly Owned Properties
Schedule of Equity Method Investments [Line Items]
Outstanding Balance	690,799	$ 217,556
Net deferred financing costs and net debt discount	(9,170)	(4,351)
Total mortgage notes payable, net	$ 681,629	213,205
Mortgages | Wholly Owned Properties | Gramercy European Property Fund III - Bridge Facility | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Interest Rate	1.50%
Outstanding Balance	$ 49,715	0
Mortgages | Wholly Owned Properties | Strategic Office Partners Portfolio Facility One | Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Interest Rate	5.02%
Outstanding Balance	$ 169,380	169,380
Mortgages | Wholly Owned Properties | Strategic Office Partners Portfolio Facility Two | Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Interest Rate	6.03%
Outstanding Balance	$ 52,020	39,540
Mortgages | Wholly Owned Properties | E-Commerce JV Portfolio Facility | Strategic Office Partners
Schedule of Equity Method Investments [Line Items]
Interest Rate	3.38%
Outstanding Balance	$ 220,000	0
Number of real estate properties pledged under debt | Property	4
Mortgages | Wholly Owned Properties | Gramercy European Property Fund III Facility 1 | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Interest Rate	1.54%
Outstanding Balance	$ 45,685	0
Number of real estate properties pledged under debt | Property	4
Mortgages | Wholly Owned Properties | Solingen, Germany | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Interest Rate	1.66%
Outstanding Balance	$ 9,785	0
Mortgages | Wholly Owned Properties | Gramercy European Property Fund III Facility 2 | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Interest Rate	1.18%
Outstanding Balance	$ 126,538	0
Number of real estate properties pledged under debt | Property	7
Mortgages | Wholly Owned Properties | Offenau, Germany | E-Commerce JV
Schedule of Equity Method Investments [Line Items]
Interest Rate	1.89%
Outstanding Balance	$ 9,125	0
Mortgages | Wholly Owned Properties | Henderson, NV | Gramercy European Property Fund III
Schedule of Equity Method Investments [Line Items]
Interest Rate	4.75%
Outstanding Balance	$ 8,551	$ 8,636

Unconsolidated Equity Investm51

Unconsolidated Equity Investments (Combined Income Statement for the Company's Joint Ventures) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Jul. 31, 2017
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations	$ (1,838)	$ 248	$ (2,764)	$ 154
Goodman Europe JV
Investments in and Advances to Affiliates [Line Items]
Ownership %					5.10%	5.10%
Gramercy European Property Fund
Investments in and Advances to Affiliates [Line Items]
Ownership %					14.20%
Gramercy European Property Fund III
Investments in and Advances to Affiliates [Line Items]
Ownership %	25.00%		25.00%
Strategic Office Partners
Investments in and Advances to Affiliates [Line Items]
Ownership %	51.00%		51.00%
Corporate Joint Venture | Goodman Europe JV
Investments in and Advances to Affiliates [Line Items]
Revenues		5,323		10,278
Operating expenses		945		1,867
Interest expense		614		1,286
Depreciation and amortization		2,024		4,045
Total expenses		3,583		7,198
Net income (loss) from operations		1,740		3,080
Gain (loss) on derivatives		0		0
Provision for taxes		(15)		(32)
Net income (loss)		1,725		3,048
Company's share in net income (loss)		88		155
Adjustments for REIT basis2		(37)		73
Company’s equity in net income (loss) within continuing operations				82
Corporate Joint Venture | Goodman Europe JV | Continuing Operations
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations		51
Corporate Joint Venture | Gramercy European Property Fund
Investments in and Advances to Affiliates [Line Items]
Revenues	$ 1,730	16,802	$ 2,212	31,875
Operating expenses	376	3,747	1,058	7,620
Interest expense	450	2,412	547	4,558
Depreciation and amortization	761	7,346	970	13,840
Total expenses	1,587	13,505	2,575	26,018
Net income (loss) from operations	143	3,297	(363)	5,857
Gain (loss) on derivatives	(781)	1,049	(781)	2,270
Loss on extinguishment of debt	(461)		(461)
Provision for taxes	(36)	(439)	(36)	(310)
Net income (loss)	(1,135)	3,907	(1,641)	7,817
Company's share in net income (loss)	(184)	527	(277)	1,040
Adjustments for REIT basis2	0	(37)	0	73
Company’s equity in net income (loss) within continuing operations	(184)		(277)	967
Corporate Joint Venture | Gramercy European Property Fund | Continuing Operations
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations		490
Corporate Joint Venture | Gramercy European Property Fund III
Investments in and Advances to Affiliates [Line Items]
Revenues	11,765	7,174	22,908	12,700
Operating expenses	4,328	2,316	8,479	3,790
Interest expense	3,390	2,055	6,503	3,565
Depreciation and amortization	5,148	2,852	9,971	5,355
Total expenses	12,866	7,223	24,953	12,710
Net income (loss) from operations	(1,101)	(49)	(2,045)	(10)
Gain (loss) on derivatives	177	(413)	669	(762)
Loss on extinguishment of debt	0		0
Provision for taxes	0	0	0	0
Net income (loss)	(924)	(462)	(1,376)	(772)
Company's share in net income (loss)	(92)	(36)	(66)	(51)
Adjustments for REIT basis2	0	0	0	0
Company’s equity in net income (loss) within continuing operations				(51)
Corporate Joint Venture | Gramercy European Property Fund III | Continuing Operations
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations	(92)	(36)	(66)
Corporate Joint Venture | Goodman UK JV
Investments in and Advances to Affiliates [Line Items]
Revenues	180	293	180	588
Operating expenses	105	225	365	527
Interest expense	0	0	0	0
Depreciation and amortization	210	261	416	636
Total expenses	315	486	781	1,163
Net income (loss) from operations	(135)	(193)	(601)	(575)
Gain (loss) on derivatives	0	0	0	0
Loss on extinguishment of debt	0		0
Provision for taxes	0	(20)	0	(28)
Net income (loss)	(135)	(213)	(601)	(603)
Company's share in net income (loss)	(108)	(171)	(481)	(483)
Adjustments for REIT basis2	(1,465)	(40)	(1,469)	129
Company’s equity in net income (loss) within continuing operations				(612)
Write-down of outside basis	1,462		1,462
Corporate Joint Venture | Goodman UK JV | Continuing Operations
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations	(1,573)	(211)	(1,950)
Corporate Joint Venture | Other
Investments in and Advances to Affiliates [Line Items]
Revenues	(5,632)	1,324	(3,638)	(7)
Operating expenses	272	399	378	975
Interest expense	0	700	666	1,341
Depreciation and amortization	20	333	353	666
Total expenses	292	1,432	1,397	2,982
Net income (loss) from operations	(5,924)	(108)	(5,035)	(2,989)
Gain (loss) on derivatives	0	0	0	0
Loss on extinguishment of debt	0		0
Provision for taxes	0	0	0	0
Net income (loss)	(5,924)	(108)	(5,035)	(2,989)
Company's share in net income (loss)	(312)	5	(292)	(150)
Adjustments for REIT basis2	0	0	0	0
Company’s equity in net income (loss) within continuing operations				(150)
Corporate Joint Venture | Other | Continuing Operations
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations	(312)	5	(292)
Corporate Joint Venture | Strategic Office Partners
Investments in and Advances to Affiliates [Line Items]
Revenues	6,771		8,936
Operating expenses	1,703		2,286
Interest expense	2,003		2,672
Depreciation and amortization	2,855		3,717
Total expenses	6,561		8,675
Net income (loss) from operations	210		261
Gain (loss) on derivatives	0		0
Loss on extinguishment of debt	0		(1,200)
Provision for taxes	0		0
Net income (loss)	210		(939)
Company's share in net income (loss)	260		(260)
Adjustments for REIT basis2	63		81
Corporate Joint Venture | Strategic Office Partners | Continuing Operations
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations	$ 323		$ (179)
Corporate Joint Venture | Gramercy European Property Fund (excluding legacy Goodman Europe Joint Venture) [Member]
Investments in and Advances to Affiliates [Line Items]
Revenues		11,479		21,597
Operating expenses		2,802		5,753
Interest expense		1,798		3,272
Depreciation and amortization		5,322		9,795
Total expenses		9,922		18,820
Net income (loss) from operations		1,557		2,777
Gain (loss) on derivatives		1,049		2,270
Provision for taxes		(424)		(278)
Net income (loss)		2,182		4,769
Company's share in net income (loss)		439		885
Adjustments for REIT basis2		0		0
Company’s equity in net income (loss) within continuing operations				$ 885
Corporate Joint Venture | Gramercy European Property Fund (excluding legacy Goodman Europe Joint Venture) [Member] | Continuing Operations
Investments in and Advances to Affiliates [Line Items]
Company’s equity in net income (loss) within continuing operations		$ 439
Gramercy European Property Fund | Goodman Europe JV
Investments in and Advances to Affiliates [Line Items]
Ownership %					94.90%

Debt Obligations (Secured Debt)

Debt Obligations (Secured Debt) (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Property	Jun. 30, 2017USD ($)Property	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Gain on extinguishment of debt	$ 83	$ 268	$ 83	$ 60
Mortgages
Debt Instrument [Line Items]
Number of real estate properties in which secured debt repaid | Property			4	2
Refinancing amount				$ 10,456
Gain on extinguishment of debt			$ 83
Real estate acquisitions | Mortgages
Debt Instrument [Line Items]
Non-recourse debt					$ 181,107
Number of Acquisitions | Property				7

Debt Obligations (Schedule of M

Debt Obligations (Schedule of Mortgage Notes Payable) (Details) - Mortgage Notes Payable $ in Thousands	Jun. 30, 2018USD ($)Property	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Outstanding Balance	$ 491,236	$ 554,498
Net deferred financing costs and net debt discount	7,979	9,023
Total mortgage notes payable, net	$ 499,215	563,521
Philadelphia, PA
Debt Instrument [Line Items]
Interest Rate	4.99%
Outstanding Balance	$ 11,743	11,943
Bridgeview, IL
Debt Instrument [Line Items]
Interest Rate	3.90%
Outstanding Balance	$ 5,745	5,838
Spartanburg, SC
Debt Instrument [Line Items]
Interest Rate	3.20%
Outstanding Balance	$ 427	632
Charleston, SC
Debt Instrument [Line Items]
Interest Rate	3.11%
Outstanding Balance	$ 181	457
Lawrence, IN
Debt Instrument [Line Items]
Interest Rate	5.02%
Outstanding Balance	$ 19,730	20,061
Charlotte, NC
Debt Instrument [Line Items]
Interest Rate	3.28%
Outstanding Balance	$ 1,185	1,538
Hawthorne, CA
Debt Instrument [Line Items]
Interest Rate	3.52%
Outstanding Balance	$ 16,960	17,207
Charleston, SC
Debt Instrument [Line Items]
Interest Rate	3.32%
Outstanding Balance	$ 633	758
Charleston, SC
Debt Instrument [Line Items]
Interest Rate	2.97%
Outstanding Balance	$ 622	746
Charleston, SC
Debt Instrument [Line Items]
Interest Rate	3.37%
Outstanding Balance	$ 622	746
Charlotte, NC
Debt Instrument [Line Items]
Interest Rate	3.38%
Outstanding Balance	$ 540	647
Des Plaines, IL
Debt Instrument [Line Items]
Interest Rate	5.54%
Outstanding Balance	$ 2,344	2,385
Waco, TX
Debt Instrument [Line Items]
Interest Rate	4.75%
Outstanding Balance	$ 14,741	14,890
Deerfield, IL
Debt Instrument [Line Items]
Interest Rate	3.71%
Outstanding Balance	$ 10,263	10,447
Winston-Salem, NC
Debt Instrument [Line Items]
Interest Rate	3.41%
Outstanding Balance	$ 2,913	3,354
Winston-Salem, NC
Debt Instrument [Line Items]
Interest Rate	3.42%
Outstanding Balance	$ 971	1,114
Logistics Portfolio - Pool 1
Debt Instrument [Line Items]
Interest Rate	4.27%
Outstanding Balance	$ 37,603	38,107
Number of real estate properties pledged under debt | Property	3
CCC Portfolio
Debt Instrument [Line Items]
Interest Rate	4.24%
Outstanding Balance	$ 22,572	22,814
Number of real estate properties pledged under debt | Property	5
Logistics Portfolio - Pool 4
Debt Instrument [Line Items]
Interest Rate	4.36%
Outstanding Balance	$ 79,500	79,500
Number of real estate properties pledged under debt | Property	6
Romeoville, IL
Debt Instrument [Line Items]
Interest Rate	3.80%
Outstanding Balance	$ 24,724	24,951
Romeoville, IL3
Debt Instrument [Line Items]
Interest Rate	9.37%
Outstanding Balance	$ 6,605	6,623
KIK USA Portfolio
Debt Instrument [Line Items]
Interest Rate	4.31%
Outstanding Balance	$ 7,001	7,154
Number of real estate properties pledged under debt | Property	3
Yuma, AZ
Debt Instrument [Line Items]
Interest Rate	5.27%
Outstanding Balance	$ 11,752	11,858
Allentown, PA
Debt Instrument [Line Items]
Interest Rate	5.16%
Outstanding Balance	$ 22,487	22,690
Spartanburg, SC
Debt Instrument [Line Items]
Interest Rate	3.72%
Outstanding Balance	$ 5,256	5,635
Natick, MA
Debt Instrument [Line Items]
Interest Rate	5.21%
Outstanding Balance	$ 31,027	31,224
Natick, MA3
Debt Instrument [Line Items]
Interest Rate	10.38%
Outstanding Balance	$ 3,447	3,469
Maple Grove, MN
Debt Instrument [Line Items]
Interest Rate	3.88%
Outstanding Balance	$ 16,201	16,380
Curtis Bay, MD
Debt Instrument [Line Items]
Interest Rate	4.31%
Outstanding Balance	$ 13,500	13,500
Rialto, CA
Debt Instrument [Line Items]
Interest Rate	3.91%
Outstanding Balance	$ 54,344	54,741
Houston, TX
Debt Instrument [Line Items]
Interest Rate	3.68%
Outstanding Balance	$ 26,000	26,000
Durham, NC
Debt Instrument [Line Items]
Interest Rate	4.02%
Outstanding Balance	$ 3,597	3,631
Charleston, SC
Debt Instrument [Line Items]
Interest Rate	3.80%
Outstanding Balance	$ 5,658	6,001
Hackettstown, NJ
Debt Instrument [Line Items]
Interest Rate	5.49%
Outstanding Balance	$ 9,387	9,455
Hutchins, TX
Debt Instrument [Line Items]
Interest Rate	5.41%
Outstanding Balance	$ 20,955	21,578
Greenwood, IN
Debt Instrument [Line Items]
Interest Rate	3.59%
Outstanding Balance	$ 0	7,257
Greenfield, IN
Debt Instrument [Line Items]
Interest Rate	3.63%
Outstanding Balance	$ 0	5,865
Logistics Portfolio - Pool 3
Debt Instrument [Line Items]
Interest Rate	3.96%
Outstanding Balance	$ 0	$ 43,302

Debt Obligations (Unsecured Deb

Debt Obligations (Unsecured Debt) (Narrative) (Details)	6 Months Ended
	Jun. 30, 2018extension	Dec. 31, 2017USD ($)	Oct. 31, 2017USD ($)	Dec. 31, 2015USD ($)
Unsecured Debt | 2015 Revolving Credit Facility - U.S. Dollar Tranche
Debt Instrument [Line Items]
Interest Rate	3.08%
Unsecured Debt | 2015 Revolving Credit Facility - Multicurrency Tranche
Debt Instrument [Line Items]
Interest Rate	1.11%
Unsecured Debt | 3-Year Term Loan
Debt Instrument [Line Items]
Interest Rate	3.23%
Unsecured Debt | 7-Year Term Loan
Debt Instrument [Line Items]
Interest Rate	3.08%
Unsecured Debt | Senior Unsecured Notes
Debt Instrument [Line Items]
Face amount		$ 500,000,000
JPMorgan Chase Bank | 2015 Revolving Credit Facility - U.S. Dollar Tranche
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 1,900,000,000
Line of credit facility, number of extensions | extension	2
JPMorgan Chase Bank | Term Loans | 3-Year Term Loan
Debt Instrument [Line Items]
Face amount				300,000,000
JPMorgan Chase Bank | Term Loans | JPM Term Loan | Federal Funds Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.50%
JPMorgan Chase Bank | Term Loans | JPM Term Loan | LIBOR 30-Day
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.00%
JPMorgan Chase Bank | Revolving Credit Facility | Line of Credit | Unsecured Credit Facility
Debt Instrument [Line Items]
Face amount				850,000,000
JPMorgan Chase Bank | Revolving Credit Facility | Line of Credit | 2015 Revolving Credit Facility - US Dollars Tranche
Debt Instrument [Line Items]
Face amount				750,000,000
JPMorgan Chase Bank | Revolving Credit Facility | Line of Credit | 2015 Revolving Credit Facility - Multicurrency Tranche
Debt Instrument [Line Items]
Face amount				100,000,000
JPMorgan Chase Bank | Revolving Credit Facility | Term Loans | Unsecured Credit Facility
Debt Instrument [Line Items]
Face amount				1,050,000,000
Capital One | Term Loans | 7-Year Term Loan
Debt Instrument [Line Items]
Face amount			$ 400,000	$ 175,000,000
Term	7 years
Minimum | Unsecured Debt | Senior Unsecured Notes
Debt Instrument [Line Items]
Interest Rate		3.89%
Minimum | JPMorgan Chase Bank | Term Loans | JPM Term Loan | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.90%
Minimum | JPMorgan Chase Bank | Term Loans | JPM Term Loan | Base Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.00%
Minimum | JPMorgan Chase Bank | Revolving Credit Facility
Debt Instrument [Line Items]
Commitment fee percentage	0.125%
Minimum | JPMorgan Chase Bank | Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.875%
Minimum | JPMorgan Chase Bank | Revolving Credit Facility | Base Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.00%
Maximum | Unsecured Debt | Senior Unsecured Notes
Debt Instrument [Line Items]
Interest Rate		4.97%
Maximum | JPMorgan Chase Bank | Term Loans | JPM Term Loan | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
Maximum | JPMorgan Chase Bank | Term Loans | JPM Term Loan | Base Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.75%
Maximum | JPMorgan Chase Bank | Revolving Credit Facility
Debt Instrument [Line Items]
Commitment fee percentage	0.30%
Maximum | JPMorgan Chase Bank | Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.55%
Maximum | JPMorgan Chase Bank | Revolving Credit Facility | Base Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.55%

Debt Obligations (Exchangeable

Debt Obligations (Exchangeable Senior Notes) (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Debt Instrument [Line Items]
Loss on extinguishment of debt		$ (83)	$ (268)	$ (83)	$ (60)
Convertible Debt | Exchangeable Senior Notes 3.75%
Debt Instrument [Line Items]
Face amount	$ 115,000
Interest Rate	3.75%
Shares issued in conversion (in shares)	5,258,420

Debt Obligations (Schedule of C

Debt Obligations (Schedule of Credit Facilities and Term Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
2015 Revolving Credit Facility - U.S. Dollar Tranche
Line of Credit Facility [Line Items]
Long-term Debt	$ 441,773
Unsecured Debt
Line of Credit Facility [Line Items]
Outstanding Balance	2,391,773	$ 2,307,162
Unamortized discount and deferred financing costs	(4,680)	(5,063)
Long-term Debt	$ 2,387,093	2,302,099
Unsecured Debt | 2015 Revolving Credit Facility - U.S. Dollar Tranche
Line of Credit Facility [Line Items]
Stated Interest Rate	3.08%
Effective Interest Rate	3.08%
Outstanding Balance	$ 405,000	345,000
Unsecured Debt | 2015 Revolving Credit Facility - Multicurrency Tranche
Line of Credit Facility [Line Items]
Stated Interest Rate	1.11%
Effective Interest Rate	1.11%
Outstanding Balance	$ 36,773	12,162
Unsecured Debt | 3-Year Term Loan
Line of Credit Facility [Line Items]
Stated Interest Rate	3.23%
Effective Interest Rate	2.33%
Outstanding Balance	$ 300,000	300,000
Unsecured Debt | 5-Year Term Loan
Line of Credit Facility [Line Items]
Stated Interest Rate	3.23%
Effective Interest Rate	2.70%
Outstanding Balance	$ 750,000	750,000
Unsecured Debt | 7-Year Term Loan
Line of Credit Facility [Line Items]
Stated Interest Rate	3.08%
Effective Interest Rate	3.00%
Outstanding Balance	$ 400,000	400,000
Unsecured Debt | 2015 Senior Notes Due 2024
Line of Credit Facility [Line Items]
Stated Interest Rate	4.97%
Effective Interest Rate	5.07%
Outstanding Balance	$ 150,000	150,000
Unsecured Debt | 2016 Senior Notes Due 2022
Line of Credit Facility [Line Items]
Stated Interest Rate	3.89%
Effective Interest Rate	4.00%
Outstanding Balance	$ 150,000	150,000
Unsecured Debt | 2016 Senior Notes Due 2025
Line of Credit Facility [Line Items]
Stated Interest Rate	4.26%
Effective Interest Rate	4.38%
Outstanding Balance	$ 100,000	100,000
Unsecured Debt | 2016 Senior Notes Due 2026
Line of Credit Facility [Line Items]
Stated Interest Rate	4.32%
Effective Interest Rate	4.43%
Outstanding Balance	$ 100,000	$ 100,000

Debt Obligations (Schedule of57

Debt Obligations (Schedule of Maturities of Long-term Debt) (Details) $ in Thousands	Jun. 30, 2018USD ($)
Long-term Debt, Fiscal Year Maturity [Abstract]
Above market interest	$ 3,299
Long-term Debt, Interest Payments, Fiscal Year Maturity [Abstract]
July 1 to December 31, 2018, interest	54,009
2019, interest	104,625
2020, interest	89,976
2021, interest	58,015
2022, interest	53,868
Thereafter, interest	64,822
Interest payments, total	428,614
Long-term Debt and Interest, Fiscal Year Maturity [Abstract]
July 1 to December 31, 2018, total	60,889
2019, total	435,075
2020, total	594,583
2021, total	827,271
2022, total	345,797
Thereafter, total	1,044,709
Net premium, total	3,311,623
2015 Revolving Credit Facility
Long-term Debt, Fiscal Year Maturity [Abstract]
July 1 to December 31, 2018	0
2,019	0
2,020	441,773
2,021	0
2,022	0
Thereafter	0
Above market interest	0
Long-term Debt	441,773
Senior Unsecured Notes
Long-term Debt, Fiscal Year Maturity [Abstract]
July 1 to December 31, 2018	0
2,019	0
2,020	0
2,021	0
2,022	150,000
Thereafter	350,000
Above market interest	0
Long-term Debt	500,000
Term Loans
Long-term Debt, Fiscal Year Maturity [Abstract]
July 1 to December 31, 2018	0
2,019	300,000
2,020	0
2,021	750,000
2,022	0
Thereafter	400,000
Above market interest	0
Long-term Debt	1,450,000
Mortgage Notes Payable
Long-term Debt, Fiscal Year Maturity [Abstract]
July 1 to December 31, 2018	6,880
2,019	30,450
2,020	62,834
2,021	19,256
2,022	141,929
Thereafter	229,887
Above market interest	0
Long-term Debt	$ 491,236

Transactions with Trustee Rel58

Transactions with Trustee Related Entities and Related Parties (Narrative) (Details) € in Thousands, $ in Thousands	Jun. 30, 2018USD ($)director	Jun. 30, 2018EUR (€)director	Dec. 31, 2017USD ($)
Related Party Transaction [Line Items]
Investments in joint ventures | $	$ 147,282		$ 70,214
Chief Executive Officer | Gramercy Europe
Related Party Transaction [Line Items]
Investments in joint ventures	1,388	€ 1,250
Managing Directors | Gramercy Europe
Related Party Transaction [Line Items]
Investments in joint ventures	$ 1,388	€ 1,250
Gramercy Europe Asset
Related Party Transaction [Line Items]
Number of managing directors | director	2	2

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) $ in Thousands	Jun. 30, 2018USD ($)Property	Dec. 31, 2017USD ($)Property
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Properties impaired | Property	2	7
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset value	$ 46,658	$ 116,011
Real estate investments | Fair Value | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset value	$ 2,592	$ 87,996

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Carrying Value and Fair Value of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Retained CDO Bonds
Financial assets:
Investments	$ 6,792
Carrying Value
Financial assets:
Loan investments	33,169	$ 22,154
Long-term debt:
2015 Revolving Credit Facility	441,773	357,162
Mortgage notes payable	499,215	563,521
Carrying Value | 3-Year Term Loan
Long-term debt:
Term loans	300,000	300,000
Carrying Value | 5-Year Term Loan
Long-term debt:
Term loans	750,000	750,000
Carrying Value | 7-Year Term Loan
Long-term debt:
Term loans	398,330	398,152
Carrying Value | Senior Unsecured Notes
Long-term debt:
Senior notes	496,990	496,785
Carrying Value | Interest rate swaps
Financial assets:
Interest rate swaps	35,212	19,668
Financial liabilities:
Interest rate swaps	0	173
Carrying Value | Retained CDO Bonds
Financial assets:
Investments	6,792	5,527
Carrying Value | Investment in CBRE Strategic Partners Asia
Financial assets:
Investments	2,062	2,820
Carrying Value | Real estate investments
Financial assets:
Investments	2,592	87,996
Fair Value
Financial assets:
Loan investments	28,872	21,362
Long-term debt:
2015 Revolving Credit Facility	441,823	357,369
Mortgage notes payable	502,870	573,826
Fair Value | 3-Year Term Loan
Long-term debt:
Term loans	300,066	300,091
Fair Value | 5-Year Term Loan
Long-term debt:
Term loans	750,573	750,678
Fair Value | 7-Year Term Loan
Long-term debt:
Term loans	400,006	400,010
Fair Value | Senior Unsecured Notes
Long-term debt:
Senior notes	494,455	513,229
Fair Value | Interest rate swaps
Financial assets:
Interest rate swaps	35,212	19,668
Financial liabilities:
Interest rate swaps	0	173
Fair Value | Retained CDO Bonds
Financial assets:
Investments	6,792	5,527
Fair Value | Investment in CBRE Strategic Partners Asia
Financial assets:
Investments	2,062	2,820
Fair Value | Real estate investments
Financial assets:
Investments	$ 2,592	$ 87,996

Fair Value Measurements (Sche61

Fair Value Measurements (Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis) (Details) - Fair Value - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	$ 46,658	$ 116,011
Financial Liabilities:		(173)
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Liabilities:		(173)
Retained CDO Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	6,792	5,527
Marketable securities | Real estate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	2,592	87,996
Marketable securities | Investment in CBRE Strategic Partners Asia
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	2,062	2,820
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	35,212	19,668
Level I
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Financial Liabilities:		0
Level I | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Liabilities:		0
Level I | Retained CDO Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level I | Marketable securities | Real estate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level I | Marketable securities | Investment in CBRE Strategic Partners Asia
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level I | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level II
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Financial Liabilities:		0
Level II | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Liabilities:		0
Level II | Retained CDO Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level II | Marketable securities | Real estate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level II | Marketable securities | Investment in CBRE Strategic Partners Asia
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level II | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	0	0
Level III
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	46,658	116,011
Financial Liabilities:		(173)
Level III | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Liabilities:		(173)
Level III | Retained CDO Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	6,792	5,527
Level III | Marketable securities | Real estate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	2,592	87,996
Level III | Marketable securities | Investment in CBRE Strategic Partners Asia
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	2,062	2,820
Level III | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets:	$ 35,212	$ 19,668

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value, Assets and Liabilities Measured on Recurring Basis, Valuation Techniques) (Details) $ in Thousands	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap liabilities fair value		$ 173
CBRE Strategic Partners Asia
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value	$ 2,062
Non-investment grade, subordinate CDO bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value	6,792
Non-investment grade, subordinate CDO bonds | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value	$ 6,792	$ 5,527
Discount Rate | CBRE Strategic Partners Asia
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in CBRE Strategic Partners Asia, discount rate	0.200
Discount Rate | Non-investment grade, subordinate CDO bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-investment grade, subordinate CDO bonds, discount rate	0.190
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value	$ 35,212
Interest rate swaps | Discount Rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, credit borrowing spread	0.0110
Interest rate swaps | Discount Rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, credit borrowing spread	0.0175

Fair Value Measurements (Fair63

Fair Value Measurements (Fair Value, Assets (Liabilities) Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 27,842
Amortization of discounts or premiums	611
Adjustments to fair value:
Unrealized loss in other comprehensive income from fair value adjustment	619
Total loss on fair value adjustments	(251)
Distributions from financial assets	(507)
Ending balance	44,066
Adjustments To Fair Value, Assets (Liabilities) [Abstract]
Termination of derivative instrument	(11,288)
Unrealized gain on derivatives	27,040
Interest rate swaps
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Amortization of discounts or premiums	(35)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	19,495
Adjustments To Fair Value, Assets (Liabilities) [Abstract]
Termination of derivative instrument	(11,288)
Unrealized gain on derivatives	27,040
Ending balance	35,212
Investment in CBRE Strategic Partners Asia
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	2,820
Adjustments to fair value:
Total loss on fair value adjustments	(251)
Distributions from financial assets	(507)
Ending balance	2,062
Retained CDO Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5,527
Amortization of discounts or premiums	646
Adjustments to fair value:
Unrealized loss in other comprehensive income from fair value adjustment	619
Ending balance	$ 6,792

Derivatives and Non-Derivativ64

Derivatives and Non-Derivative Hedging Instruments (Schedule of Derivative Instruments) (Details) - Not Designated as Hedging Instrument £ in Thousands, $ in Thousands	Jun. 30, 2018USD ($)	Jun. 30, 2018GBP (£)
Derivative [Line Items]
Fair Value	$ 35,212
Interest Rate Swap Strike Rate 4.55%
Derivative [Line Items]
Notional Value	$ 14,741
Strike Rate	4.55%	4.55%
Fair Value	$ 64
Interest Rate Swap Strike Rate 1.22%
Derivative [Line Items]
Notional Value	$ 100,000
Strike Rate	1.22%	1.22%
Fair Value	$ 472
Interest Rate Swap Strike Rate 1.23%
Derivative [Line Items]
Notional Value	$ 100,000
Strike Rate	1.23%	1.23%
Fair Value	$ 470
Interest Rate Swap Strike Rate 1.24%
Derivative [Line Items]
Notional Value	$ 100,000
Strike Rate	1.24%	1.24%
Fair Value	$ 465
Interest Rate Swap Strike Rate 1.60%
Derivative [Line Items]
Notional Value	$ 750,000
Strike Rate	1.60%	1.60%
Fair Value	$ 19,539
Interest Rate Swap Strike Rate 1.82%
Derivative [Line Items]
Notional Value	$ 175,000
Strike Rate	1.82%	1.82%
Fair Value	$ 6,853
Interest Rate Swap Strike Rate 1.95%
Derivative [Line Items]
Notional Value	$ 60,000
Strike Rate	1.95%	1.95%
Fair Value	$ 2,025
Interest Rate Swap Strike Rate 2.01%
Derivative [Line Items]
Notional Value	$ 40,000
Strike Rate	2.01%	2.01%
Fair Value	$ 1,243
Interest Rate Swap Strike Rate 1.96%
Derivative [Line Items]
Notional Value	$ 39,500
Strike Rate	1.96%	1.96%
Fair Value	$ 1,298
Interest Rate Swap Strike Rate 1.96%
Derivative [Line Items]
Notional Value	$ 31,500
Strike Rate	1.96%	1.96%
Fair Value	$ 1,038
Interest Rate Swap Strike Rate 2.00%
Derivative [Line Items]
Notional Value	$ 31,500
Strike Rate	2.00%	2.00%
Fair Value	$ 991
Interest Rate Swap Strike Rate 1.95%
Derivative [Line Items]
Notional Value	$ 22,500
Strike Rate	1.95%	1.95%
Fair Value	$ 754
Net Investment Hedge in GBP-denominated investments
Derivative [Line Items]
Notional Value | £		£ 9,000
Fair Value	0
Net Investment Hedge in EUR-denominated investments
Derivative [Line Items]
Notional Value | £		£ 21,300
Fair Value	$ 0

Derivatives and Non-Derivativ65

Derivatives and Non-Derivative Hedging Instruments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Cumulative effect of accounting changes					$ 663
Interest rate swaps
Derivative [Line Items]
Derivative asset, fair value	$ 35,212		$ 35,212
Amounts reclassified from OCI			(9,553)
Interest expense to be recognized			1,024
Net Investment Hedge in GBP-denominated Investments
Derivative [Line Items]
Net loss on hedge ineffectiveness	$ 1,027	$ (4,196)	$ 568	$ (5,119)
Accumulated Other Comprehensive Income (Loss)
Derivative [Line Items]
Cumulative effect of accounting changes					$ 103

Derivatives and Non-Derivativ66

Derivatives and Non-Derivative Hedging Instruments (Gain Recognized On Interest Rate Swaps) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Gain reclassified from accumulated other comprehensive income (loss) into interest expense	$ (11,017)	$ 271	$ (10,749)	$ 539
Gain on derivative instruments	14,970	0	14,970	0
Cumulative effect of accounting changes					$ 663
Interest Expense
Derivative [Line Items]
Gain recognized in accumulated other comprehensive income (loss)		0		0
Interest Expense | Interest rate swaps
Derivative [Line Items]
Gain recognized in accumulated other comprehensive income (loss)	4,990		27,143
Gain reclassified from accumulated other comprehensive income (loss) into interest expense	271	271	539	539
Gain recognized in interest expense (ineffective portion)	0	0	0	46
Total recognized in interest expense on statements of operations	271	$ 271	539	$ 585
Accounting Standards Update 2017-02
Derivative [Line Items]
Cumulative effect of accounting changes	$ 103		$ 103

Shareholders' Equity (Deficit67

Shareholders' Equity (Deficit) of the Company (ESPP, DRIP, Share Repurchase and ATM Equity Offering Program Narrative) (Details)	1 Months Ended				3 Months Ended		6 Months Ended
	Sep. 30, 2017shares	Dec. 31, 2016	Jul. 31, 2016USD ($)	Jun. 30, 2016shares	Jun. 30, 2018$ / sharesshares	Mar. 31, 2018$ / shares	Jun. 30, 2018$ / sharesshares	Dec. 31, 2017$ / sharesshares
Class of Stock [Line Items]
Capital units, authorized (in shares)					500,000,000		500,000,000	500,000,000
Common stock, par value (in usd per share) | $ / shares					$ 0.01		$ 0.01	$ 0.01
Capital stock, par value (in usd per share) | $ / shares								$ 0.01
Common stock, shares authorized (in shares)					490,000,000		490,000,000	490,000,000
Preferred stock, shares authorized (in shares)					10,000,000		10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)					3,500,000		3,500,000
Dividends declared (in usd per share) | $ / shares					$ 0.375	$ 0.375
Stock split conversion ratio		0.3333
ESPP shares authorized (in shares)					250,000		250,000
ESPP purchase discount percent					90.00%		90.00%
ESPP shares held (in shares)					1,374		1,374
Shares registered for DRIP (in shares)				3,333,333
Dividend reinvestment program proceeds (in shares)							3,363
Shares available for issuance under DRIP (in shares)					3,322,410		3,322,410
At-the-market offering | $			$ 375,000,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)					3,500,000		3,500,000	3,500,000
Preferred stock, shares outstanding (in shares)					3,500,000		3,500,000	3,500,000
Preferred stock, shares issued (in shares)					3,500,000		3,500,000	3,500,000
Exchangeable Senior Notes 3.75% | Convertible Debt
Class of Stock [Line Items]
Shares issued in conversion (in shares)	5,258,420
Percent of instrument converted	100.00%
GPT Operating Partnership LP
Class of Stock [Line Items]
Partnership units (in units)					160,792,820		160,792,820

Shareholders' Equity (Deficit68

Shareholders' Equity (Deficit) of the Company (Dividends Paid) (Details) - $ / shares	3 Months Ended
	Jun. 30, 2018	Mar. 31, 2018
Equity [Abstract]
Dividends declared (in usd per share)	$ 0.375	$ 0.375

Shareholders' Equity (Deficit69

Shareholders' Equity (Deficit) of the Company (Preferred Stock) (Narrative) (Details) - $ / shares	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)	3,500,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)	3,500,000	3,500,000
Preferred stock, redemption price per share (in usd per share)	$ 25
7.125% Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, dividend rate (in usd per share)	$ 1.78125

Shareholders' Equity (Deficit70

Shareholders' Equity (Deficit) of the Company (Equity Plan Summaries and Earnings Per Share) (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Outside Interests in Operating Partnership
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities (in shares)		5,934,765	560,443	5,490,217	590,547
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted shares outstanding (in shares)		341,089		341,089		347,676
2016 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)		2,625,800		2,625,800
Grants in period (in shares)				1,129,130
Shares vesting percentage				67.20%
Share-based compensation expense		$ 617	$ 755	$ 1,158	$ 1,572
2016 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, not yet recognized		4,141		$ 4,141
Share based compensation expense, not yet recognized, period of recognition				23 months
Outperformance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		1,151	$ 1,070	$ 2,289	$ 2,126
Share based compensation expense, not yet recognized		$ 9,037		$ 9,037
Share based compensation expense, not yet recognized, period of recognition				32 months
Exchangeable Senior Notes 3.75% | Convertible Debt
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of instrument converted	100.00%

Shareholders' Equity (Deficit71

Shareholders' Equity (Deficit) of the Company (Schedule of Calculation of Numerator and Denominator in Earnings Per Share) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator - Income (loss)
Net income (loss) from continuing operations	$ 20,754	$ 5,985	$ 32,363	$ (2,087)
Net loss from discontinued operations	0	(28)	0	(52)
Net income (loss) before net gain on disposals	20,754	5,957	32,363	(2,139)
Net gain on disposals	4,523	2,002	20,778	19,379
Net income	25,277	7,959	53,141	17,240
Net (income) loss attributable to noncontrolling interest	(845)	113	(1,647)	(41)
Less: Nonforfeitable dividends allocated to participating shareholders	(206)	(337)	(409)	(635)
Less: Preferred share dividends	(1,558)	(1,558)	(3,117)	(3,117)
Net income available to common shares outstanding	$ 22,668	$ 6,177	$ 47,968	$ 13,447
Denominator – Weighted average shares
Weighted average basic shares outstanding (in shares)	160,420,278	148,542,916	160,414,240	144,746,251
Effect of dilutive securities
Unvested non-participating share based payment awards (in shares)	0	86,452	0	79,552
Option (in shares)	13,073	19,196	11,051	14,471
Exchangeable Senior Notes (in shares)	0	1,265,879	0	1,125,662
Diluted shares (in shares)	160,433,351	149,914,443	160,425,291	145,965,936

Shareholders' Equity (Deficit72

Shareholders' Equity (Deficit) of the Company (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Equity [Abstract]
Net unrealized gain on derivative securities	$ 42,670	$ 15,630
Net unrealized gain on debt instruments	1,036	417
Foreign currency translation adjustments:
Net gain on non-derivative net investment hedges	865	297
Other foreign currency translation adjustments	(6,966)	(5,734)
Reclassification of swap gain (loss) into interest expense	(8,583)	2,166
Cumulative effect of accounting change	103	0
Total accumulated other comprehensive income	29,125	$ 12,776
Write-off on non-derivative net investment hedge	$ 1,851

Partners' Capital of the Oper73

Partners' Capital of the Operating Partnership (Narrative) (Details) - GPT Operating Partnership LP	Jun. 30, 2018shares
Limited Partners' Capital Account [Line Items]
Partnership units (in units)	160,792,820
Ownership interest in Operating Partnership	96.42%
Ownership percentage by noncontrolling owners	3.58%
Noncontrolling Interest
Limited Partners' Capital Account [Line Items]
Partnership units (in units)	5,959,858

Partners' Capital of the Oper74

Partners' Capital of the Operating Partnership (Calculation of Earnings Per Share) (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2016	Jun. 30, 2018USD ($)shares	Jun. 30, 2017USD ($)shares	Jun. 30, 2018USD ($)shares	Jun. 30, 2017USD ($)shares
Numerator - Income (loss)
Net income (loss) from continuing operations		$ 20,754	$ 5,985	$ 32,363	$ (2,087)
Net loss from discontinued operations		0	(28)	0	(52)
Net income (loss) before net gain on disposals		20,754	5,957	32,363	(2,139)
Net gain on disposals		4,523	2,002	20,778	19,379
Net income		25,277	7,959	53,141	17,240
Less: Nonforfeitable dividends allocated to participating unitholders		(206)	(337)	(409)	(635)
Less: Preferred unit distributions		$ (1,558)	$ (1,558)	$ (3,117)	$ (3,117)
Effect of dilutive securities
Unvested non-participating unit based payment awards (in units) | shares		0	86,452	0	79,552
Option (in units) | shares		13,073	19,196	11,051	14,471
Exchangeable Senior Notes (in units) | shares		0	1,265,879	0	1,125,662
Stock split conversion ratio	0.3333
GPT Operating Partnership LP
Numerator - Income (loss)
Net income (loss) from continuing operations		$ 20,754	$ 5,985	$ 32,363	$ (2,087)
Net loss from discontinued operations		0	(28)	0	(52)
Net income (loss) before net gain on disposals		20,754	5,957	32,363	(2,139)
Net gain on disposals		4,523	2,002	20,778	19,379
Net income		25,277	7,959	53,141	17,240
Less: Net loss attributable to noncontrolling interest in other partnerships		0	137	0	17
Less: Nonforfeitable dividends allocated to participating unitholders		(206)	(337)	(409)	(635)
Less: Preferred unit distributions		(1,558)	(1,558)	(3,117)	(3,117)
Net income available to common unitholders		$ 23,513	$ 6,201	$ 49,615	$ 13,505
Denominator – Weighted average shares
Weighted average basic units outstanding (in units) | shares		166,355,043	149,103,359	165,904,457	145,336,798
Effect of dilutive securities
Unvested non-participating unit based payment awards (in units) | shares		0	86,452	0	79,552
Option (in units) | shares		13,073	19,196	11,051	14,471
Exchangeable Senior Notes (in units) | shares		0	1,265,879	0	1,125,662
Diluted shares (in shares) | shares		166,368,116	150,474,886	165,915,508	146,556,483

Noncontrolling Interests (Narra

Noncontrolling Interests (Narrative) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)Propertyshares	Jun. 30, 2017shares	Dec. 31, 2017USD ($)shares
Noncontrolling Interest [Line Items]
Capital shares reserved for future issuance (in shares)	5,300,343
Noncontrolling interest in operating partnership (in usd) | $	$ 156,293		$ 113,530
Long-term Incentive Plan Units
Noncontrolling Interest [Line Items]
Capital shares reserved for future issuance (in shares)	659,515
GPT Operating Partnership LP
Noncontrolling Interest [Line Items]
Ownership percentage by noncontrolling owners	3.58%
Limited partners' capital, units outstanding	159,128,950		159,035,964
Noncontrolling interest in operating partnership (in usd) | $	$ 156,293		$ 113,530
GPT Operating Partnership LP | Long-term Incentive Plan Units
Noncontrolling Interest [Line Items]
Shares vested (in shares)	659,515
Limited Partner | GPT Operating Partnership LP
Noncontrolling Interest [Line Items]
Limited partners' capital, units outstanding	5,300,343
Shares converted	6,038	134,607
Noncontrolling interest in operating partnership (in usd) | $	$ 156,293		$ 113,530
Strategic Office Partners | GPT Operating Partnership LP
Noncontrolling Interest [Line Items]
Acquisitions (in units)	1,566,961
Number of operating properties | Property	4

Noncontrolling Interests (Nonco

Noncontrolling Interests (Noncontrolling Interest in the Operating Partnership) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 113,530
Balance at end of period	156,293
GPT Operating Partnership LP
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	113,530
Balance at end of period	156,293
Limited Partner | GPT Operating Partnership LP
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	113,530
Issuance of noncontrolling interests in the Operating Partnership	37,558
Redemption of noncontrolling interests in the Operating Partnership	(130)
Net income attribution	1,647
Fair value adjustments	7,448
Dividends	(3,760)
Balance at end of period	$ 156,293

Commitments and Contingencies77

Commitments and Contingencies (Narrative) (Details) € in Thousands, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2017USD ($)Property	Jun. 30, 2018USD ($)Property	Jun. 30, 2018EUR (€)Property	Jun. 30, 2018USD ($)Property	Jun. 30, 2018EUR (€)Property	Dec. 31, 2017Property	Jun. 30, 2018EUR (€)Property	Oct. 31, 2017USD ($)	Oct. 31, 2017EUR (€)
Commitments And Contingencies [Line Items]
Commitment amount		$ 40,265		$ 40,265
Contributions to unconsolidated equity investments				81,356
E-Commerce JV
Commitments And Contingencies [Line Items]
Investment in unconsolidated equity investment		28,186		28,186			€ 23,478
Aggregate cost								$ 310,643	€ 262,622
Payments to investments		25,170	€ 20,964	$ 22,710	€ 18,987
Number of Acquisitions | Property				11	11
E-Commerce JV | Parent Company
Commitments And Contingencies [Line Items]
Aggregate cost		61,730		$ 61,730			€ 52,187
Strategic Office Partners
Commitments And Contingencies [Line Items]
Commitment amount		110,000		110,000
Contributions to unconsolidated equity investments				61,304
Cash contributions to equity method investment	$ 30,000	$ 14,435		$ 15,565
Economic Ownership		51.00%		51.00%			51.00%
Number of Acquisitions | Property	6	2	2	4	4	6
Gramercy European Property Fund III
Commitments And Contingencies [Line Items]
Commitment amount		$ 400,000		$ 400,000
Cash contributions to equity method investment		2,950		2,950
Investment in unconsolidated equity investment		$ 32,427		$ 32,427
Economic Ownership		25.00%		25.00%			25.00%
Gramercy European Property Fund III | Parent Company
Commitments And Contingencies [Line Items]
Commitment amount		$ 100,000		$ 100,000
Build-to-suit Property
Commitments And Contingencies [Line Items]
Properties obligated to build | Property		2		2			2
Development Property
Commitments And Contingencies [Line Items]
Properties obligated to build | Property		2		2			2
Number of Acquisitions | Property				1	1

Commitments and Contingencies78

Commitments and Contingencies (Schedule of Future Minimum Rental Payments) (Details) $ in Thousands	Jun. 30, 2018USD ($)
Ground Leases - Operating
July 1 to December 31, 2018, operating	$ 1,266
2019, operating	2,593
2020, operating	2,596
2021, operating	2,567
2022, operating	2,598
Thereafter, operating	73,175
Total minimum rent expense, operating	84,795
Ground Leases - Capital
July 1 to December 31, 2018, capital	0
2019, capital	0
2020, capital	0
2021, capital	0
2022, capital	0
Thereafter, capital	329
Total minimum rent expense, capital	329
Total
July 1 to December 31, 2018	1,266
2,019	2,593
2,020	2,596
2,021	2,567
2,022	2,598
Thereafter	73,504
Total	$ 85,124

Supplemental Cash Flow Inform79

Supplemental Cash Flow Information (Non-Cash Activities Recognized in Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Interest paid	$ 50,194	$ 44,441
Income taxes paid	218	296
Proceeds from 1031 exchanges from sale of real estate	5	170,210
Use of funds from 1031 exchanges for acquisitions of real estate	(5)	(140,987)
Non-cash activity:
Fair value adjustment to noncontrolling interest in the Operating Partnership	7,448	576
Debt assumed in acquisition of real estate	0	3,680
Debt transferred in disposition of real estate	0	(10,456)
Non-cash acquisition of consolidated VIE	0	24,930
Dividend reinvestment plan proceeds	81	103
Redemption of units of noncontrolling interest in the Operating Partnership for common shares	(130)	(2,697)
Contributions to unconsolidated equity investments for units of noncontrolling interests in the operating partnership	$ 37,558	$ 0

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2018USD ($)Property	Jun. 30, 2018USD ($)impaired_property	Jun. 30, 2017USD ($)impaired_property	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jul. 01, 2018USD ($)	Dec. 31, 2017USD ($)
Subsequent Event [Line Items]
Investment in unconsolidated equity investment		$ 147,282		$ 147,282			$ 70,214
Number of properties | impaired_property		2	3
Gross proceeds		$ 19,971	$ 183,302	$ 130,983	$ 234,985
Subsequent Event
Subsequent Event [Line Items]
Number of properties | Property	2
Gross proceeds	$ 36,650
Gramercy European Property Fund III
Subsequent Event [Line Items]
Economic Ownership		25.00%		25.00%
Gramercy European Property Fund III | Subsequent Event
Subsequent Event [Line Items]
Proceeds from sale of investment	$ 45,382
Investment in unconsolidated equity investment						$ 388,000