Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of above and below Market Leases	$ 13,454
Provision for impairment, net of tax	1,672	$ 374
Cash flows from investing activities:
Proceeds from sale of real estate investments	82,533	3,227
Partnership Interest [Member]
Cash flows from operating activities:
Net income	(91,493)	(53,465)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	97,194	88,525
Amortization of deferred loan costs and debt premiums	2,921	2,471
Amortization of above and below Market Leases	(13,090)	(8,181)
Share-based Compensation	3,475	3,397
Equity in income of investments in real estate partnerships	(30,828)	(10,349)
Gain on sale of real estate, net of tax	(16,490)	(96)
Provision for impairment, net of tax	1,672	16,054
Gain (Loss) on Extinguishment of Debt	10,591	162
Distribution of earnings from operations of investments in real estate partnerships	(14,417)	(13,319)
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	5,719	0
Deferred compensation expense	2,314	40
Realized and unrealized gain on investments	(2,354)	(30)
Increase (Decrease) in Accounts and Other Receivables	(9,050)	(4,296)
Changes in assets and liabilities:
Deferred leasing costs	(2,491)	(1,189)
Other assets	(11,212)	(476)
Accounts payable and other liabilities	(8,908)	(13,793)
Tenants’ security, escrow deposits and prepaid rent	(10,671)	2,253
Net cash provided by operating activities	131,364	149,868
Cash flows from investing activities:
Acquisition of operating real estate	(15,722)	(20,071)
Payments for Deposits on Real Estate Acquisitions	(1,250)	0
Real estate development and capital improvements	(39,929)	(51,968)
Proceeds from sale of real estate investments	82,533	3,227
Payments for (Proceeds from) Loans Receivable	0	(462)
Investments in real estate partnerships	(19,587)	(39,330)
Proceeds from Equity Method Investment, Distribution, Return of Capital	41,587	2,328
Dividends on investment securities	116	71
Acquisition of investment securities	(5,359)	(7,543)
Proceeds from sale of investment securities	4,612	6,542
Net cash provided by (used in) investing activities	47,001	(107,206)
Cash flows from financing activities:
Payments Related to Tax Withholding for Share-based Compensation	(6,148)	(6,755)
Payments for Repurchase of Common Stock	(32,778)	(124,989)
Proceeds from sale of treasury stock	8	99
Distributions to limited partners in consolidated partnerships, net	(1,485)	(1,018)
Dividends paid to common stockholders	(97,812)	(95,043)
Repayments of Unsecured Debt	250,000	0
Proceeds from Issuance of Unsecured Debt	298,983	299,511
Proceeds from unsecured credit facilities	110,000	185,000
Repayment of unsecured credit facilities	(145,000)	(245,000)
Proceeds from notes payable	0	1,740
Repayments of Notes Payable	(40,315)	0
Scheduled principal payments	(2,235)	(2,773)
Payment of loan costs	(3,342)	(9,179)
Payment for Debt Extinguishment or Debt Prepayment Cost	10,647	0
Net cash (used in) provided by financing activities	(180,771)	1,593
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(2,406)	44,255
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	42,784	93,636
Supplemental disclosure of cash flow information:
Cash paid for interest (net of capitalized interest of $1,015 and $2,179 in 2019 and 2018, respectively)	42,421	30,467
Proceeds from Income Tax Refunds	(15)	(407)
Supplemental disclosure of non-cash transactions:
Noncash or Part Noncash Acquisition, Debt Assumed	0	9,700
Common stock issued under dividend reinvestment plan	383	358
Stock-based compensation, net of capitalization	573	837
Contributions from limited partners in consolidated partnerships, net	881	0
Common stock issued for dividend reinvestment in trust	238	205
Contribution of stock awards into trust	1,328	637
Distribution of stock held in trust	167	317
Unrealized Gain (Loss) on Securities	174	(128)
Parent Company [Member]
Capital Expenditures Incurred but Not yet Paid	10,494	0
Cash flows from operating activities:
Net income	(91,493)	(53,465)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	97,194	88,525
Amortization of deferred loan costs and debt premiums	2,921	2,471
Amortization of above and below Market Leases	(13,090)	(8,181)
Share-based Compensation	3,475	3,397
Equity in income of investments in real estate partnerships	(30,828)	(10,349)
Gain on sale of real estate, net of tax	(16,490)	(96)
Provision for impairment, net of tax	1,672	16,054
Gain (Loss) on Extinguishment of Debt	10,591	162
Distribution of earnings from operations of investments in real estate partnerships	(14,417)	(13,319)
(Payments for) Proceeds from Settlement of Derivative Instrument	(5,719)	0
Deferred compensation expense	2,314	40
Realized and unrealized gain on investments	(2,354)	(30)
Increase (Decrease) in Accounts and Other Receivables	(9,050)	(4,296)
Changes in assets and liabilities:
Deferred leasing costs	(2,491)	(1,189)
Other assets	(11,212)	(476)
Accounts payable and other liabilities	(8,908)	(13,793)
Tenants’ security, escrow deposits and prepaid rent	(10,671)	2,253
Net cash provided by operating activities	131,364	149,868
Cash flows from investing activities:
Acquisition of operating real estate	(15,722)	(20,071)
Payments for Deposits on Real Estate Acquisitions	(1,250)	0
Real estate development and capital improvements	(39,929)	(51,968)
Proceeds from sale of real estate investments	82,533	3,227
Payments for (Proceeds from) Loans Receivable	0	(462)
Investments in real estate partnerships	(19,587)	(39,330)
Proceeds from Equity Method Investment, Distribution, Return of Capital	41,587	2,328
Dividends on investment securities	116	71
Acquisition of investment securities	(5,359)	(7,543)
Proceeds from sale of investment securities	4,612	6,542
Net cash provided by (used in) investing activities	47,001	(107,206)
Cash flows from financing activities:
Payments Related to Tax Withholding for Share-based Compensation	(6,148)	(6,755)
Payments for Repurchase of Common Stock	(32,778)	(124,989)
Proceeds from sale of treasury stock	8	99
Distributions to limited partners in consolidated partnerships, net	(1,485)	(1,018)
Distributions to exchangeable operating partnership unit holders	(204)	(194)
Dividends paid to common stockholders	(97,608)	(94,849)
Repayments of Unsecured Debt	250,000	0
Proceeds from Issuance of Unsecured Debt	298,983	299,511
Proceeds from unsecured credit facilities	110,000	185,000
Repayment of unsecured credit facilities	(145,000)	(245,000)
Proceeds from notes payable	0	1,740
Repayments of Notes Payable	(40,315)	0
Scheduled principal payments	(2,235)	(2,773)
Payment of loan costs	(3,342)	(9,179)
Payment for Debt Extinguishment or Debt Prepayment Cost	10,647	0
Net cash (used in) provided by financing activities	(180,771)	1,593
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(2,406)	44,255
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	42,784	93,636
Supplemental disclosure of cash flow information:
Cash paid for interest (net of capitalized interest of $1,015 and $2,179 in 2019 and 2018, respectively)	42,421	30,467
Proceeds from Income Tax Refunds	(15)	(407)
Supplemental disclosure of non-cash transactions:
Noncash or Part Noncash Acquisition, Debt Assumed	0	9,700
Common stock issued under dividend reinvestment plan	383	358
Stock-based compensation, net of capitalization	573	837
Contributions from limited partners in consolidated partnerships, net	881	0
Common stock issued for dividend reinvestment in trust	238	205
Contribution of stock awards into trust	1,328	637
Distribution of stock held in trust	167	317
Unrealized Gain (Loss) on Securities	$ 174	$ (128)