Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Real estate investments at cost:
Notes receivable	$ 0	$ 15,803
Parent Company [Member]
Real estate investments at cost:
Property, Plant and Equipment, Gross	10,752,552	10,578,430
Properties in development	164,001	314,391
Gross real estate investments at cost	10,916,553	10,892,821
Less: accumulated depreciation	1,433,120	1,339,771
Total Cost Net of Accumulated Depreciation	9,483,433	9,553,050
Investments in real estate partnerships	451,220	386,304
Net real estate investments	9,934,653	9,939,354
Real Estate Held-for-sale	102,163	0
Cash and cash equivalents	37,151	45,370
Restricted cash	6,089	4,011
Tenant and other receivables, net of allowance for doubtful accounts and straight-line rent reserves of $14,790 and $12,728 at June 30, 2018 and December 31, 2017, respectively	155,540	170,985
Deferred Costs, Leasing, Net	83,686	80,044
Acquired lease intangible assets, less accumulated amortization of $188,246 and $148,280 at June 30, 2018 and December 31, 2017, respectively	432,951	478,826
Other assets	429,497	427,127
Total assets	11,181,730	11,145,717
Liabilities:
Notes payable	3,118,002	2,971,715
Unsecured credit facilities	713,498	623,262
Accounts payable and other liabilities	215,300	234,272
Acquired lease intangible liabilities, less accumulated amortization of $75,179 and $56,550 at June 30, 2018 and December 31, 2017, respectively	517,018	537,401
Tenants’ security, escrow deposits and prepaid rent	49,124	46,013
Total liabilities	4,612,942	4,412,663
Commitments and contingencies	0	0
Stockholders’ equity/Partners' capital:
Common stock, $0.01 par value per share, 220,000,000 shares authorized; 169,435,301 and 171,364,908 shares issued at June 30, 2018 and December 31, 2017, respectively	1,694	1,714
Treasury stock at cost, 381,258 and 366,628 shares held at June 30, 2018 and December 31, 2017, respectively	(19,268)	(18,307)
Additional paid in capital	7,751,375	7,873,104
Accumulated other comprehensive income (loss)	10,317	(6,289)
Distributions in excess of net income	(1,216,018)	(1,158,170)
Total stockholders’ equity	6,528,100	6,692,052
Noncontrolling interests:
Exchangeable operating partnership units, aggregate redemption value of $21,722 and $24,206 at June 30, 2018 and December 31, 2017, respectively	10,765	10,907
Limited partners’ interests in consolidated partnerships	29,923	30,095
Stockholders' Equity Attributable to Noncontrolling Interest	40,688	41,002
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(6,568,788)	(6,733,054)
Total liabilities and equity	11,181,730	11,145,717
Partnership Interest [Member]
Real estate investments at cost:
Property, Plant and Equipment, Gross	10,752,552	10,578,430
Properties in development	164,001	314,391
Gross real estate investments at cost	10,916,553	10,892,821
Less: accumulated depreciation	1,433,120	1,339,771
Total Cost Net of Accumulated Depreciation	9,483,433	9,553,050
Investments in real estate partnerships	451,220	386,304
Net real estate investments	9,934,653	9,939,354
Real Estate Held-for-sale	102,163	0
Cash and cash equivalents	37,151	45,370
Restricted cash	6,089	4,011
Tenant and other receivables, net of allowance for doubtful accounts and straight-line rent reserves of $14,790 and $12,728 at June 30, 2018 and December 31, 2017, respectively	155,540	170,985
Deferred Costs, Leasing, Net	83,686	80,044
Acquired lease intangible assets, less accumulated amortization of $188,246 and $148,280 at June 30, 2018 and December 31, 2017, respectively	432,951	478,826
Other assets	429,497	427,127
Total assets	11,181,730	11,145,717
Liabilities:
Notes payable	3,118,002	2,971,715
Unsecured credit facilities	713,498	623,262
Accounts payable and other liabilities	215,300	234,272
Acquired lease intangible liabilities, less accumulated amortization of $75,179 and $56,550 at June 30, 2018 and December 31, 2017, respectively	517,018	537,401
Tenants’ security, escrow deposits and prepaid rent	49,124	46,013
Total liabilities	4,612,942	4,412,663
Commitments and contingencies	0	0
Stockholders’ equity/Partners' capital:
General partner; 169,435,301 and 171,364,908 units outstanding at June 30, 2018 and December 31, 2017, respectively	6,517,783	6,698,341
Limited partners; 349,902 units outstanding at June 30, 2018 and December 31, 2017	10,765	10,907
Accumulated other comprehensive income (loss)	10,317	(6,289)
Total partners’ capital	6,538,865	6,702,959
Noncontrolling interests:
Limited partners’ interests in consolidated partnerships	29,923	30,095
Total noncontrolling interests	29,923	30,095
Total equity	6,568,788	6,733,054
Total liabilities and equity	$ 11,181,730	$ 11,145,717