Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
OPERATING ACTIVITIES:
Net income	$ 24,920,000	$ 19,237,000
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation expense	32,114,000	27,276,000
Depreciation and amortization, including amortization of debt issuance costs	97,053,000	99,312,000
Deferred rent	(18,342,000)	(6,265,000)
Income from unconsolidated real estate ventures, net	(1,791,000)	(1,934,000)
Amortization of above- and below-market lease intangibles, net	(272,000)	143,000
Amortization of lease incentives	3,789,000	3,148,000
Reduction of gain on bargain purchase	0	(7,606,000)
Loss on extinguishment of debt	1,889,000	4,457,000
Gain on sale of real estate	(39,033,000)	(33,851,000)
Net unrealized loss (gain) on derivative financial instruments not designated as cash flow hedges	48,000	(1,551,000)
Losses on operating lease receivables	497,000	1,565,000
Return on capital from unconsolidated real estate ventures	1,493,000	5,168,000
Other non-cash items	271,000	829,000
Changes in operating assets and liabilities:
Tenant and other receivables	(6,232,000)	5,877,000
Other assets, net	(2,940,000)	(5,263,000)
Accounts payable and accrued expenses	(28,513,000)	(30,213,000)
Other liabilities, net	(12,168,000)	(1,996,000)
Net cash provided by operating activities	52,783,000	93,545,000
INVESTING ACTIVITIES:
Development costs, construction in progress and real estate additions	(181,007,000)	(165,718,000)
Deposits for real estate acquisitions	(8,525,000)	0
Proceeds from sale of real estate	117,676,000	232,882,000
Acquisition of interests in unconsolidated real estate ventures, net of cash acquired	0	(386,000)
Distributions of capital from unconsolidated real estate ventures	7,557,000	1,350,000
Investments in and advances to unconsolidated real estate ventures	(4,409,000)	(16,167,000)
Other	0	(665,000)
Net cash (used in) provided by investing activities	(68,708,000)	51,296,000
FINANCING ACTIVITIES:
Acquisition of ownership interest in consolidated real estate venture	0	(548,000)
Finance lease payments	(66,000)	(52,000)
Borrowings under mortgages payable	0	41,344,000
Borrowings under revolving credit facility	0	35,000,000
Borrowings under unsecured term loans	0	50,000,000
Repayments of mortgages payable	(480,674,000)	(170,021,000)
Repayments of revolving credit facility	0	115,022,000
Debt issuance costs	515,000	0
Proceeds from the issuance of common stock, net of issuance costs	473,527,000	0
Dividends paid to common shareholders	(69,473,000)	(53,077,000)
Distributions to redeemable noncontrolling interests	(9,734,000)	(9,214,000)
Contributions from noncontrolling interests	125,000	0
Distributions to noncontrolling interests	(19,000)	(120,000)
Net cash used in financing activities	(86,829,000)	(221,710,000)
Net decrease in cash and cash equivalents and restricted cash	(102,754,000)	(76,869,000)
Cash and cash equivalents and restricted cash as of the beginning of the period	399,532,000	338,557,000
Cash and cash equivalents and restricted cash as of the end of the period	296,778,000	261,688,000
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AS OF END OF THE PERIOD:
Cash and cash equivalents and restricted cash	399,532,000	338,557,000
SUPPLEMENTAL DISCLOSURE OF CASH FLOW AND NON-CASH INFORMATION:
Cash paid for interest (net of capitalized interest of $14,953 and $9,182 in 2019 and 2018)	29,179,000	31,741,000
Accrued capital expenditures included in accounts payable and accrued expenses	89,048,000	60,735,000
Write-off of fully depreciated assets	26,974,000	10,973,000
Deconsolidation of 1900 N Street	0	95,923,000
Fair value of OP Unit redemptions	(57,318,000)	0
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	35,318,000	0
Lease liabilities related to operating right-of-use assets (1)	37,922,000	0
Cash paid for amounts included in the measurement of lease liabilities for operating leases	$ 3,068,000	$ 0