Segment Reporting - Summary of Segment Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 63,773,000	$ 70,229,000	$ 135,193,000	$ 144,216,000
Depreciation and amortization	(33,793,000)	(30,304,000)	(67,170,000)	(60,637,000)
Property operating expenses, other operating and real estate taxes	(27,503,000)	(22,405,000)	(51,270,000)	(43,542,000)
General and administrative expenses	(8,720,000)	(9,034,000)	(17,790,000)	(17,357,000)
Impairment charge	0	(1,400,000)	(51,549,000)	(1,400,000)
Gain on disposition of properties	485,000		485,000	2,014,000
Operating (loss) income	(5,758,000)	7,086,000	(52,101,000)	23,294,000
Interest income	2,095,000	4,142,000	5,024,000	6,412,000
Interest and Other Income		4,142,000		6,412,000
Realized and unrealized holding gains on investments and other	87,811,000		87,281,000
Equity in (losses) earnings of unconsolidated affiliates	(786,000)	3,559,000	469,000	5,830,000
Interest expense	(18,319,000)	(19,759,000)	(36,621,000)	(37,618,000)
Income tax (provision) benefit	(137,000)	(265,000)	815,000	(219,000)
Net income (loss)	64,906,000	(5,237,000)	4,867,000	(2,301,000)
Net (income) loss attributable to noncontrolling interests	(45,496,000)	14,317,000	6,129,000	23,578,000
Net income attributable to Acadia	19,410,000	9,080,000	10,996,000	21,277,000
Real estate at cost	4,162,224,000	3,939,525,000	4,162,224,000	3,939,525,000
Total assets	4,328,748,000	4,209,922,000	4,328,748,000	4,209,922,000	$ 4,309,114,000
Cash paid for acquisition of real estate			21,208,000	138,716,000
Cash paid for development and property improvement costs			20,533,000	55,872,000
Core Portfolio
Segment Reporting Information [Line Items]
Realized and unrealized holding gains on investments and other			0
Operating Segments | Core Portfolio
Segment Reporting Information [Line Items]
Revenues	38,602,000	43,212,000	78,535,000	89,899,000
Depreciation and amortization	(18,150,000)	(15,092,000)	(35,207,000)	(30,770,000)
Property operating expenses, other operating and real estate taxes	(17,961,000)	(12,217,000)	(29,775,000)	(24,211,000)
General and administrative expenses	0	0	0	0
Impairment charge	0	0	0	0
Gain on disposition of properties	0		0	0
Operating (loss) income	2,491,000	15,903,000	13,553,000	34,918,000
Interest income	0		0
Interest and Other Income		327,000		327,000
Realized and unrealized holding gains on investments and other	0		0
Equity in (losses) earnings of unconsolidated affiliates	(1,070,000)	3,254,000	572,000	5,524,000
Interest expense	(8,602,000)	(6,839,000)	(16,852,000)	(13,532,000)
Income tax (provision) benefit	0	0	0	0
Net income (loss)	(7,181,000)	12,645,000	(2,727,000)	27,237,000
Net (income) loss attributable to noncontrolling interests	5,068,000	425,000	6,284,000	385,000
Net income attributable to Acadia	(2,113,000)	13,070,000	3,557,000	27,622,000
Real estate at cost	2,362,334,000	2,154,630,000	2,362,334,000	2,154,630,000
Total assets	2,323,986,000	2,267,022,000	2,323,986,000	2,267,022,000
Cash paid for acquisition of real estate			19,963,000	49,402,000
Cash paid for development and property improvement costs			6,443,000	26,876,000
Operating Segments | Opportunity Funds
Segment Reporting Information [Line Items]
Revenues	25,171,000	27,017,000	56,658,000	54,317,000
Depreciation and amortization	(15,643,000)	(15,212,000)	(31,963,000)	(29,867,000)
Property operating expenses, other operating and real estate taxes	(9,542,000)	(10,188,000)	(21,495,000)	(19,331,000)
General and administrative expenses	0	0	0	0
Impairment charge	0	(1,400,000)	(51,549,000)	(1,400,000)
Gain on disposition of properties	485,000		485,000	2,014,000
Operating (loss) income	471,000	217,000	(47,864,000)	5,733,000
Interest income	0		0
Interest and Other Income		1,586,000		1,586,000
Realized and unrealized holding gains on investments and other	87,751,000		87,751,000
Equity in (losses) earnings of unconsolidated affiliates	284,000	305,000	(103,000)	306,000
Interest expense	(9,717,000)	(12,920,000)	(19,769,000)	(24,086,000)
Income tax (provision) benefit	0	0	0	0
Net income (loss)	78,789,000	(10,812,000)	20,015,000	(16,461,000)
Net (income) loss attributable to noncontrolling interests	(50,564,000)	13,892,000	(155,000)	23,193,000
Net income attributable to Acadia	28,225,000	3,080,000	19,860,000	6,732,000
Real estate at cost	1,799,890,000	1,784,895,000	1,799,890,000	1,784,895,000
Total assets	1,870,070,000	1,848,238,000	1,870,070,000	1,848,238,000
Cash paid for acquisition of real estate			1,245,000	89,314,000
Cash paid for development and property improvement costs			14,090,000	28,996,000
Operating Segments | Structured Financing
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depreciation and amortization	0	0	0	0
Property operating expenses, other operating and real estate taxes	0	0	0	0
General and administrative expenses	0	0	0	0
Impairment charge	0	0	0	0
Gain on disposition of properties	0		0	0
Operating (loss) income	0	0	0	0
Interest income	2,095,000		5,024,000
Interest and Other Income		2,229,000		4,499,000
Realized and unrealized holding gains on investments and other	60,000		(470,000)
Equity in (losses) earnings of unconsolidated affiliates	0	0	0	0
Interest expense	0	0	0	0
Income tax (provision) benefit	0	0	0	0
Net income (loss)	2,155,000	2,229,000	4,554,000	4,499,000
Net (income) loss attributable to noncontrolling interests	0	0	0	0
Net income attributable to Acadia	2,155,000	2,229,000	4,554,000	4,499,000
Real estate at cost	0	0	0	0
Total assets	134,692,000	94,662,000	134,692,000	94,662,000
Cash paid for acquisition of real estate			0	0
Cash paid for development and property improvement costs			0	0
Unallocated
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depreciation and amortization	0	0	0	0
Property operating expenses, other operating and real estate taxes	0	0	0	0
General and administrative expenses	(8,720,000)	(9,034,000)	(17,790,000)	(17,357,000)
Impairment charge	0	0	0	0
Gain on disposition of properties	0		0	0
Operating (loss) income	(8,720,000)	(9,034,000)	(17,790,000)	(17,357,000)
Interest income	0		0
Interest and Other Income		0		0
Realized and unrealized holding gains on investments and other	0		0
Equity in (losses) earnings of unconsolidated affiliates	0	0	0	0
Interest expense	0	0	0	0
Income tax (provision) benefit	(137,000)	(265,000)	815,000	(219,000)
Net income (loss)	(8,857,000)	(9,299,000)	(16,975,000)	(17,576,000)
Net (income) loss attributable to noncontrolling interests	0	0	0	0
Net income attributable to Acadia	(8,857,000)	(9,299,000)	(16,975,000)	(17,576,000)
Real estate at cost	0	0	0	0
Total assets	$ 0	$ 0	0	0
Cash paid for acquisition of real estate			0	0
Cash paid for development and property improvement costs			$ 0	$ 0