Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities:
Net income (loss)	$ 26,098	$ 3,451
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of building and building improvements	42,302	30,106
Amortization of leasing costs and intangibles, including ground leasehold interests	54,602	46,415
Amortization of above and below market leases, net	2,219	(2,147)
Amortization of deferred financing costs	2,004	3,132
Amortization of debt premium	(170)	(235)
Accretion in excess of cash receipts on notes receivable	(1,228)	0
Deferred rent	(11,864)	(11,368)
Write off of tenant improvement reserves	(900)	0
Gain from sale of depreciable operating property	0	(7,728)
Gain on acquisition of unconsolidated entity	(666)	0
Unrealized gain on interest rate swaps	(21)	0
Loss from investment in unconsolidated entities	1,203	1,177
Stock-based compensation	14	9
Change in operating assets and liabilities:
Deferred leasing costs and other assets	3,437	(4,221)
Restricted cash	6,013	(5,774)
Accrued expenses and other liabilities	(9,513)	7,031
Due to affiliates, net	(5,418)	996
Net cash provided by operating activities	108,112	60,844
Investing Activities:
Acquisition of properties, net	(7,897)	(356,811)
Cash assumed from SOR merger	0	8,557
Proceeds from disposition of properties	0	34,878
Real estate acquisition deposits	0	(3,000)
Real estate funds held for exchange	47,031	(11,048)
Reserves for tenant improvements	1,965	3,361
Improvements to real estate	(6,758)	(6,156)
Payments for construction in progress, net	(7,045)	(2,090)
Real estate development, net of unpaid construction costs	0	(44,425)
Mortgage receivable from affiliate	25,741	0
Distributions of capital from investment in unconsolidated entities	5,933	5,720
Net cash provided by (used in) investing activities	58,970	(371,014)
Financing Activities:
Proceeds from borrowings - Term Loan (July 2015)	75,000	640,000
Principal payoff of Unsecured Term Loan (May 2014)	0	(300,000)
Principal payoff of secured indebtedness - Mortgage Debt	(17,375)	0
Principal payoff of secured indebtedness - Signature Office REIT Credit Facility	0	(173,000)
Principal amortization payments on secured indebtedness	(3,363)	(1,506)
Deferred financing costs	(740)	(4,895)
Offering costs	0	(54)
Purchase of noncontrolling interest	(18,129)	0
Repurchase of preferred units	0	(190,894)
Repurchase of common stock	(29,933)	(5,422)
Distributions paid on preferred units subject to redemption	0	(10,013)
Distributions to noncontrolling interests	(3,244)	(2,585)
Distributions to common stockholders	(51,991)	(35,379)
Net cash (used in) provided by financing activities	(149,019)	269,477
Net increase (decrease) in cash and cash equivalents	18,063	(40,693)
Cash and cash equivalents at the beginning of the period	21,944	68,915
Cash and cash equivalents at the end of the period	40,007	28,222
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest	33,236	3,566
Supplemental Disclosures of Non-cash Transactions:
Decrease in fair value of interest rate swap agreements	(17,312)	(15,344)
Limited partnership units of the operating partnership issued in conjunction with the acquisition of real estate assets by affiliates	11,941	0
Mortgage debt assumed in conjunction with the contribution of real estate assets plus a discount of $535	22,441	0
Common stock issued pursuant to the distribution reinvestment plan	39,252	39,254
Common stock redemptions funded subsequent to period-end	11,598	8,397
Unsecured Revolver, May 2014
Financing Activities:
Proceeds from borrowings - Revolver	0	490,100
Principal payoff of secured indebtedness - Revolver	0	(490,100)
Revolver Loan, July 2015
Financing Activities:
Proceeds from borrowings - Revolver	40,100	353,225
Principal payoff of secured indebtedness - Revolver	$ (139,344)	$ 0