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	$ 302,760	$ 432,644	$ 387,268
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation of buildings and tenant improvements	297,158	272,422	256,250
Amortization of deferred leasing and other costs	55,855	54,801	55,967
Amortization of deferred financing costs	9,155	6,536	5,867
Straight-line rental income and expense, net	(25,865)	(21,197)	(24,605)
Impairment charges	5,626	0	0
Loss on debt extinguishment	32,900	6,320	388
Gain (Loss) on Involuntary Conversion	(4,312)	(2,259)	0
Gains on land and property sales	(138,269)	(242,543)	(219,114)
Third-party construction contracts, net	(2,511)	9,254	(15,400)
Other accrued revenues and expenses, net	29,333	8,476	47,711
Operating distributions received in excess of (less than) equity in earnings from unconsolidated joint ventures	4,606	(18,556)	(9,925)
Net cash provided by operating activities	566,436	505,898	484,407
Cash flows from investing activities:
Development of real estate investments	(573,544)	(446,801)	(577,383)
Payments to Acquire Commercial Real Estate	(383,672)	(210,224)	(348,107)
Acquisition of land and other real estate assets	(248,413)	(388,202)	(244,262)
Second generation tenant improvements, leasing costs and building improvements	(41,099)	(47,549)	(53,474)
Other deferred leasing costs	(45,545)	(38,509)	(39,380)
Other assets	(4,868)	(10,777)	(14,535)
Proceeds from the repayments of notes receivable from property sales	110,000	162,550	154,107
Proceeds from land and property sales, net	336,255	432,662	511,391
Capital distributions from unconsolidated joint ventures	876	26,272	23,133
Capital contributions and advances to unconsolidated joint ventures	(6,211)	(34,496)	(5,920)
Net cash used for investing activities	(856,221)	(555,074)	(594,430)
Cash flows from financing activities:
Proceeds from issuance of common shares, net	187,856	272,761	34,913
Proceeds from unsecured debt	663,123	582,284	450,000
Payments on unsecured debt	(546,972)	(255,812)	(7,190)
Proceeds from secured debt financings	18,400	0	0
Payments on secured indebtedness including principal amortization	(13,457)	(45,515)	(232,234)
Borrowings (repayments) on line of credit, net	295,000	(30,000)	30,000
Distributions to common shareholders	(355,287)	(318,702)	(291,502)
Distributions to noncontrolling interests, net	(3,347)	(2,648)	(2,456)
Tax payments on stock-based compensation awards	(4,360)	(6,825)	(8,459)
Change in book overdrafts	1,941	138	(22,088)
Cash settlement of interest rate swaps	0	(35,569)	0
Other financing activities	163	(10,183)	0
Deferred financing costs	(7,483)	(4,839)	(9,071)
Net cash provided by (used for) financing activities	235,577	145,090	(58,087)
Net (decrease) increase in cash, cash equivalents and restricted cash	(54,208)	95,914	(168,110)
Cash, cash equivalents and restricted cash at beginning of year	(121,431)	(25,517)	(193,627)
Cash, cash equivalents and restricted cash at end of year	67,223	121,431	25,517
Non-cash investing and financing activities:
Lease liabilities arising from right-of-use assets	20,883	40,467	0
Carrying amount of pre-existing ownership interest in acquired property	0	0	5,034
Non-cash property contribution from noncontrolling interests	0	0	3,200
Assumption of indebtedness and other liabilities in real estate acquisitions	39,966	0	0
Conversion of Limited Partner Units to common shares	0	1,624	(269)
Duke Realty Limited Partnership [Member]
Cash flows from operating activities:
Net income	302,760	432,644	387,268
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation of buildings and tenant improvements	297,158	272,422	256,250
Amortization of deferred leasing and other costs	55,855	54,801	55,967
Amortization of deferred financing costs	9,155	6,536	5,867
Straight-line rental income and expense, net	(25,865)	(21,197)	(24,605)
Impairment charges	5,626	0	0
Loss on debt extinguishment	32,900	6,320	388
Gain (Loss) on Involuntary Conversion	(4,312)	(2,259)	0
Gains on land and property sales	(138,269)	(242,543)	(219,114)
Third-party construction contracts, net	(2,511)	9,254	(15,400)
Other accrued revenues and expenses, net	29,333	8,476	47,711
Operating distributions received in excess of (less than) equity in earnings from unconsolidated joint ventures	4,606	(18,556)	(9,925)
Net cash provided by operating activities	566,436	505,898	484,407
Cash flows from investing activities:
Development of real estate investments	(573,544)	(446,801)	(577,383)
Payments to Acquire Commercial Real Estate	(383,672)	(210,224)	(348,107)
Acquisition of land and other real estate assets	(248,413)	(388,202)	(244,262)
Second generation tenant improvements, leasing costs and building improvements	(41,099)	(47,549)	(53,474)
Other deferred leasing costs	(45,545)	(38,509)	(39,380)
Other assets	(4,868)	(10,777)	(14,535)
Proceeds from the repayments of notes receivable from property sales	110,000	162,550	154,107
Proceeds from land and property sales, net	336,255	432,662	511,391
Capital distributions from unconsolidated joint ventures	876	26,272	23,133
Capital contributions and advances to unconsolidated joint ventures	(6,211)	(34,496)	(5,920)
Net cash used for investing activities	(856,221)	(555,074)	(594,430)
Cash flows from financing activities:
Contributions from the General Partner	187,856	272,761	34,913
Proceeds from unsecured debt	663,123	582,284	450,000
Payments on unsecured debt	(546,972)	(255,812)	(7,190)
Proceeds from secured debt financings	18,400	0	0
Payments on secured indebtedness including principal amortization	(13,457)	(45,515)	(232,234)
Borrowings (repayments) on line of credit, net	295,000	(30,000)	30,000
Distributions to common shareholders	(358,484)	(321,469)	(294,233)
Distributions to noncontrolling interests, net	(150)	119	275
Tax payments on stock-based compensation awards	(4,360)	(6,825)	(8,459)
Change in book overdrafts	1,941	138	(22,088)
Cash settlement of interest rate swaps	0	(35,569)	0
Other financing activities	163	(10,183)	0
Deferred financing costs	(7,483)	(4,839)	(9,071)
Net cash provided by (used for) financing activities	235,577	145,090	(58,087)
Net (decrease) increase in cash, cash equivalents and restricted cash	(54,208)	95,914	(168,110)
Cash, cash equivalents and restricted cash at beginning of year	(121,431)	(25,517)	(193,627)
Cash, cash equivalents and restricted cash at end of year	67,223	121,431	25,517
Non-cash investing and financing activities:
Lease liabilities arising from right-of-use assets	20,883	40,467	0
Carrying amount of pre-existing ownership interest in acquired property	0	0	5,034
Non-cash property contribution from noncontrolling interests	0	0	3,200
Assumption of indebtedness and other liabilities in real estate acquisitions	39,966	0	0
Conversion of Limited Partner Units to common shares	$ 0	$ 1,624	$ (269)