CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 207,293	$ 215,229	$ 277,926
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	290,353	268,045	249,882
Depreciation of non-real estate furniture, fixtures and equipment	8,955	5,085	4,400
Revenue reversals (recoveries) for doubtful accounts (Notes 2 and 17)	18,997	(3,433)	5,685
Non-cash amortization of share-based compensation awards (Note 15)	30,245	27,007	27,932
Non-cash amortization of deferred financing costs and net debt discounts	2,958	1,427	1,084
Non-cash amortization of net below market rents (Note 5)	(7,603)	(9,206)	(9,748)
Gains on sales of depreciable operating properties (Note 4)	(35,536)	(36,802)	(142,926)
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements (Note 10)	(17,547)	(19,190)	(18,429)
Straight-line rents	(67,826)	(72,023)	(26,976)
Amortization of right of use ground lease assets (Note 2)	825	683
Loss on early extinguishment of debt (Note 9)	0	0	12,623
Gain on sale of land (Note 4)	0	0	(11,825)
Net change in other operating assets	(3,685)	(14,476)	(7,930)
Net change in other operating liabilities	28,161	24,175	48,345
Net cash provided by operating activities	455,590	386,521	410,043
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(486,565)	(845,464)	(489,236)
Expenditures for operating properties and other capital assets	(129,500)	(147,687)	(166,440)
Net proceeds received from dispositions (Note 4)	74,937	124,421	364,300
(Increase) decrease in acquisition-related deposits	(1,000)	0	36,000
Expenditures for acquisitions of development properties and undeveloped land (Note 3)	0	(173,291)	(311,299)
Expenditures for acquisitions of operating properties (Note 3)	0	(186,258)	(257,340)
Proceeds received from repayment of note receivable	0	0	15,100
Net cash used in investing activities	(542,128)	(1,228,279)	(808,915)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common stock (Note 13)	721,665	353,722	130,693
Net proceeds from the issuance of unsecured debt (Note 9)	772,297	499,390	648,537
Repayments of unsecured debt (Note 9)	(150,000)	0	(261,823)
Borrowings on unsecured revolving credit facility	190,000	1,110,000	765,000
Repayments on unsecured revolving credit facility	(435,000)	(910,000)	(690,000)
Principal payments and repayments of secured debt (Note 9)	(5,137)	(76,309)	(3,584)
Financing costs	(6,594)	(6,678)	(6,262)
Repurchase of common stock and restricted stock units (Note 15)	(14,082)	(14,556)	(16,553)
Distributions to noncontrolling interests in consolidated property partnerships	(15,247)	(12,952)	(11,803)
Dividends and distributions paid to common stockholders and common unitholders	(224,578)	(196,252)	(179,411)
Proceeds from exercise of stock options	0	703	41
Borrowings on unsecured debt	0	0	120,000
Contributions from noncontrolling interests in consolidated property partnerships	0	0	8,273
Net cash provided by financing activities	833,324	747,068	503,108
Net increase (decrease) in cash and cash equivalents and restricted cash	746,786	(94,690)	104,236
Cash and cash equivalents and restricted cash, beginning of year	76,344	171,034	66,798
Cash and cash equivalents and restricted cash, end of year	$ 823,130	$ 76,344	$ 171,034