Real Estate - Dispositions (Details) - Disposal Group, Not Discontinued Operations - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale Price	$ 281,338
Gain/(Loss) on Sale	48,886
STATEMENTS OF INCOME
Rental revenues		$ 2,840
Expenses		(4,803)
Loss from continuing operations of disposed properties before gain on disposition of properties		(1,963)
Net income attributable to noncontrolling interests		1,405
Net loss attributable to Acadia		$ (558)
Fund III \| New Hyde Park Shopping Center
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale Price	22,075
Gain/(Loss) on Sale	6,433
Fund II \| 216th Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale Price	30,579
Gain/(Loss) on Sale	6,543
Fund II \| City Point Condominium Tower I
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale Price	96,000
Gain/(Loss) on Sale	(810)
Fund II \| 260 E 161th Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale Price	105,684
Gain/(Loss) on Sale	31,537
Fund IV \| 1151 Third Avenue
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale Price	27,000
Gain/(Loss) on Sale	$ 5,183

Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Gross

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Proceeds from Sale of Real Estate Held-for-investment, Gross

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Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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