Segment Reporting - Summary of Segment Information (Parenthetical) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net income attributable to Acadia	$ (9,030)	$ 10,458	$ 1,966	$ 31,735
Real estate at cost	4,168,291	4,012,134	4,168,291	4,012,134
Total assets	4,251,408	4,329,545	4,251,408	4,329,545	$ 4,309,114
Net (income) loss attributable to noncontrolling interests	(29,259)	(1,618)	(35,388)	(25,196)
Opportunity Funds \| Fund II's City Point Property
Segment Reporting Information [Line Items]
Real estate at cost	606,600		606,600
Total assets	598,100		598,100
Net (income) loss attributable to noncontrolling interests			176,500		$ 173,500
Operating Segments \| Core Portfolio
Segment Reporting Information [Line Items]
Net income attributable to Acadia	499	10,486	4,058	38,108
Real estate at cost	2,365,426	2,190,281	2,365,426	2,190,281
Total assets	2,291,730	2,316,683	2,291,730	2,316,683
Net (income) loss attributable to noncontrolling interests	(1,407)	(263)	(7,691)	(648)
Operating Segments \| Core Portfolio \| Town Center
Segment Reporting Information [Line Items]
Net income attributable to Acadia			1,000	3,700
Operating Segments \| Opportunity Funds
Segment Reporting Information [Line Items]
Net income attributable to Acadia	(2,922)	7,849	16,936	14,581
Real estate at cost	1,802,865	1,821,853	1,802,865	1,821,853
Total assets	1,824,880	1,918,055	1,824,880	1,918,055
Net (income) loss attributable to noncontrolling interests	$ (27,852)	$ (1,355)	$ (27,697)	$ (24,548)

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