Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net income (loss)	$ 96,832	$ 19,574	$ 178,457	$ (5,209)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			151,476	174,353
Amortization of deferred loan costs and debt premiums			3,479	5,237
(Accretion) and amortization of above and below market lease intangibles, net			(11,174)	(22,456)
Stock-based compensation, net of capitalization			5,894	7,217
Equity in income of investments in real estate partnerships	(435)	(2,824)	(12,101)	(14,242)
Gain on sale of real estate, net of tax			(31,479)	(45,453)
Provision for impairment of real estate	135	230	135	1,014
Goodwill impairment				132,128
Distribution of earnings from investments in real estate partnerships			36,545	18,655
Settlement of derivative instruments			(2,472)
Deferred compensation expense			2,856	(441)
Realized and unrealized (gain) loss on investments			(3,606)	599
Changes in assets and liabilities:
Tenant and other receivables			12,711	(24,111)
Deferred leasing costs			(4,884)	(3,732)
Other assets			(8,490)	(8,499)
Accounts payable and other liabilities			7,168	10,982
Tenants’ security, escrow deposits and prepaid rent			772	(8,623)
Net cash provided by operating activities			325,287	217,419
Cash flows from investing activities:
Acquisition of operating real estate				(16,867)
Advance deposits refunded on acquisition of operating real estate			500	100
Real estate development and capital improvements			(72,735)	(107,852)
Proceeds from sale of real estate investments			107,577	115,614
Issuance of notes receivable			(20)	(440)
Investments in real estate partnerships			(21,382)	(42,088)
Return of capital from investments in real estate partnerships			58,699	23,235
Dividends on investment securities			67	140
Acquisition of investment securities			(14,065)	(7,062)
Proceeds from sale of investment securities			14,393	7,094
Net cash provided by (used in) investing activities			73,034	(28,126)
Cash flows from financing activities:
Net proceeds from common stock issuance				125,616
Repurchase of common shares in conjunction with equity award plans			(4,017)	(5,405)
Proceeds from sale of treasury stock			96	62
Distributions to limited partners in consolidated partnerships, net			(1,989)	(1,644)
Distributions to exchangeable operating partnership unit holders			(907)	(910)
Dividends paid to common stockholders			(201,233)	(199,971)
Proceeds from issuance of fixed rate unsecured notes, net				598,830
Proceeds from unsecured credit facilities				610,000
Repayment of unsecured credit facilities			(265,000)	(830,000)
Repayment of notes payable			(3,962)	(3,891)
Scheduled principal payments			(5,678)	(5,128)
Payment of loan costs			(7,468)	(5,056)
Net cash (used in) provided by financing activities			(490,158)	282,503
Net (decrease) increase in cash and cash equivalents and restricted cash			(91,837)	471,796
Cash and cash equivalents and restricted cash at beginning of the period			378,450	115,562	$ 115,562
Cash and cash equivalents and restricted cash at end of the period	286,613	587,358	286,613	587,358	378,450
Supplemental disclosure of cash flow information:
Cash paid for interest (net of capitalized interest of $1,865 and $2,449 in 2021 and 2020, respectively)			70,112	72,013
Cash paid for income taxes, net of refunds			314	576
Supplemental disclosure of non-cash transactions:
Acquisition of real estate previously held within investments in real estate partnerships				5,986
Mortgage loan assumed with the acquisition of real estate				16,359
Common stock issued for partnership units exchanged			99
Issuance of exchangeable operating partnership units				1,275
Change in accrued capital expenditures			6,947	2,965
Common stock issued under dividend reinvestment plan	392	377	768	756
Stock-based compensation capitalized			424	604
Common stock and exchangeable operating partnership dividends declared but not paid			101,520
Common stock issued for dividend reinvestment in trust			552	540
Contribution of stock awards into trust			1,416	1,352
Distribution of stock held in trust			415	441
Change in fair value of securities			272	326
Partnership Interest [Member]
Cash flows from operating activities:
Net income (loss)	96,832	19,574	178,457	(5,209)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			151,476	174,353
Amortization of deferred loan costs and debt premiums			3,479	5,237
(Accretion) and amortization of above and below market lease intangibles, net			(11,174)	(22,456)
Stock-based compensation, net of capitalization			5,894	7,217
Equity in income of investments in real estate partnerships	(435)	(2,824)	(12,101)	(14,242)
Gain on sale of real estate, net of tax			(31,479)	(45,453)
Provision for impairment of real estate	135	230	135	1,014
Goodwill impairment				132,128
Distribution of earnings from investments in real estate partnerships			36,545	18,655
Settlement of derivative instruments			(2,472)
Deferred compensation expense			2,856	(441)
Realized and unrealized (gain) loss on investments			(3,606)	599
Changes in assets and liabilities:
Tenant and other receivables			12,711	(24,111)
Deferred leasing costs			(4,884)	(3,732)
Other assets			(8,490)	(8,499)
Accounts payable and other liabilities			7,168	10,982
Tenants’ security, escrow deposits and prepaid rent			772	(8,623)
Net cash provided by operating activities			325,287	217,419
Cash flows from investing activities:
Acquisition of operating real estate				(16,867)
Advance deposits refunded on acquisition of operating real estate			500	100
Real estate development and capital improvements			(72,735)	(107,852)
Proceeds from sale of real estate investments			107,577	115,614
Issuance of notes receivable			(20)	(440)
Investments in real estate partnerships			(21,382)	(42,088)
Return of capital from investments in real estate partnerships			58,699	23,235
Dividends on investment securities			67	140
Acquisition of investment securities			(14,065)	(7,062)
Proceeds from sale of investment securities			14,393	7,094
Net cash provided by (used in) investing activities			73,034	(28,126)
Cash flows from financing activities:
Net proceeds from common stock issuance				125,616
Repurchase of common shares in conjunction with equity award plans			(4,017)	(5,405)
Proceeds from sale of treasury stock			96	62
Distributions to limited partners in consolidated partnerships, net			(1,989)	(1,644)
Dividends paid to common stockholders			(202,140)	(200,881)
Proceeds from issuance of fixed rate unsecured notes, net				598,830
Proceeds from unsecured credit facilities				610,000
Repayment of unsecured credit facilities			(265,000)	(830,000)
Repayment of notes payable			(3,962)	(3,891)
Scheduled principal payments			(5,678)	(5,128)
Payment of loan costs			(7,468)	(5,056)
Net cash (used in) provided by financing activities			(490,158)	282,503
Net (decrease) increase in cash and cash equivalents and restricted cash			(91,837)	471,796
Cash and cash equivalents and restricted cash at beginning of the period			378,450	115,562	115,562
Cash and cash equivalents and restricted cash at end of the period	$ 286,613	$ 587,358	286,613	587,358	$ 378,450
Supplemental disclosure of cash flow information:
Cash paid for interest (net of capitalized interest of $1,865 and $2,449 in 2021 and 2020, respectively)			70,112	72,013
Cash paid for income taxes, net of refunds			314	576
Supplemental disclosure of non-cash transactions:
Acquisition of real estate previously held within investments in real estate partnerships				5,986
Mortgage loan assumed with the acquisition of real estate				16,359
Issuance of exchangeable operating partnership units				1,275
Change in accrued capital expenditures			6,947	2,965
Common stock issued under dividend reinvestment plan			768	756
Stock-based compensation capitalized			424	604
Common stock and exchangeable operating partnership dividends declared but not paid			101,520
Common stock issued for dividend reinvestment in trust			552	540
Contribution of stock awards into trust			1,416	1,352
Distribution of stock held in trust			415	441
Change in fair value of securities			272	$ 326
Common unit exchanged for common stock of Parent Company			$ 99