Segment Reporting - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 77,786	$ 73,327	$ 70,229	$ 73,985	$ 69,727	$ 65,527	$ 62,201	$ 62,226	$ 295,327	$ 259,681	$ 248,552
Depreciation and amortization									(125,443)	(117,549)	(104,934)
Property operating expenses, other operating and real estate taxes									(90,468)	(80,248)	(78,088)
General and administrative expenses									(35,416)	(34,343)	(33,756)
Impairment charge		(300)	(1,400)						(1,721)		(14,455)
Gain on disposition of properties									30,324	5,140	48,886
Operating income									72,603	32,681	66,205
Interest income									7,988	13,231	29,143
Equity in earnings of unconsolidated affiliates inclusive of gains on disposition of properties									8,922	9,302	23,371
Interest expense									(73,788)	(69,978)	(58,978)
Other income									6,947		5,571
Income tax provision									(1,468)	(934)	(1,004)
Net income (loss)	14,665	8,840	(5,237)	2,936	(6,671)	(2,597)	(2,270)	(4,160)	21,204	(15,698)	64,308
Net loss (income) attributable to noncontrolling interests	6,645	1,618	14,317	9,261	13,801	11,822	9,935	11,579	31,841	47,137	(2,838)
Net income attributable to Acadia	21,310	$ 10,458	$ 9,080	$ 12,197	7,130	$ 9,225	$ 7,665	$ 7,419	53,045	31,439	61,470
Real estate at cost	4,099,542				3,697,805				4,099,542	3,697,805
Total Assets	4,309,114				3,958,780				4,309,114	3,958,780
Cash paid for acquisition of real estate and leasehold interest									358,704
Cash paid for acquisition of real estate									319,673	147,985	200,429
Cash paid for development and property improvement costs									89,270	94,834	108,142
Operating Segments | Core Portfolio
Segment Reporting Information [Line Items]
Revenues									173,177	166,816	168,795
Depreciation and amortization									(61,819)	(60,903)	(61,705)
Property operating expenses, other operating and real estate taxes									(47,032)	(44,060)	(44,169)
General and administrative expenses									0	0	0
Impairment charge									0		0
Gain on disposition of properties									16,771	0	0
Operating income									81,097	61,853	62,921
Interest income									0	0	0
Equity in earnings of unconsolidated affiliates inclusive of gains on disposition of properties									9,020	7,415	3,735
Interest expense									(28,304)	(27,575)	(28,618)
Other income									327		5,571
Income tax provision									0	0	0
Net income (loss)									62,140	41,693	43,609
Net loss (income) attributable to noncontrolling interests									337	752	(1,107)
Net income attributable to Acadia									62,477	42,445	42,502
Real estate at cost	2,264,010				2,069,439				2,264,010	2,069,439
Total Assets	2,350,833				2,232,695				2,350,833	2,232,695
Cash paid for acquisition of real estate and leasehold interest									173,892
Cash paid for acquisition of real estate										1,343	0
Cash paid for development and property improvement costs									22,724	32,662	42,026
Operating Segments | Funds
Segment Reporting Information [Line Items]
Revenues									122,150	92,865	79,757
Depreciation and amortization									(63,624)	(56,646)	(43,229)
Property operating expenses, other operating and real estate taxes									(43,436)	(36,188)	(33,919)
General and administrative expenses									0	0	0
Impairment charge									(1,721)		(14,455)
Gain on disposition of properties									13,553	5,140	48,886
Operating income									26,922	5,171	37,040
Interest income									0	0	0
Equity in earnings of unconsolidated affiliates inclusive of gains on disposition of properties									(98)	1,887	19,636
Interest expense									(45,484)	(42,403)	(30,360)
Other income									6,620		0
Income tax provision									0	0	0
Net income (loss)									(12,040)	(35,345)	26,316
Net loss (income) attributable to noncontrolling interests									31,504	46,385	(1,731)
Net income attributable to Acadia									19,464	11,040	24,585
Real estate at cost	1,835,532				1,628,366				1,835,532	1,628,366
Total Assets	1,843,338				1,616,472				1,843,338	1,616,472
Cash paid for acquisition of real estate and leasehold interest									184,812
Cash paid for acquisition of real estate										146,642	200,429
Cash paid for development and property improvement costs									66,546	62,172	66,116
Operating Segments | Structured Financing
Segment Reporting Information [Line Items]
Revenues									0	0	0
Depreciation and amortization									0	0	0
Property operating expenses, other operating and real estate taxes									0	0	0
General and administrative expenses									0	0	0
Impairment charge									0		0
Gain on disposition of properties									0	0	0
Operating income									0	0	0
Interest income									7,988	13,231	29,143
Equity in earnings of unconsolidated affiliates inclusive of gains on disposition of properties									0	0	0
Interest expense									0	0	0
Other income									0		0
Income tax provision									0	0	0
Net income (loss)									7,988	13,231	29,143
Net loss (income) attributable to noncontrolling interests									0	0	0
Net income attributable to Acadia									7,988	13,231	29,143
Real estate at cost	0				0				0	0
Total Assets	114,943				109,613				114,943	109,613
Cash paid for acquisition of real estate and leasehold interest									0
Cash paid for acquisition of real estate										0	0
Cash paid for development and property improvement costs									0	0	0
Unallocated
Segment Reporting Information [Line Items]
Revenues									0	0	0
Depreciation and amortization									0	0	0
Property operating expenses, other operating and real estate taxes									0	0	0
General and administrative expenses									(35,416)	(34,343)	(33,756)
Impairment charge									0		0
Gain on disposition of properties									0	0	0
Operating income									(35,416)	(34,343)	(33,756)
Interest income									0	0	0
Equity in earnings of unconsolidated affiliates inclusive of gains on disposition of properties									0	0	0
Interest expense									0	0	0
Other income									0		0
Income tax provision									(1,468)	(934)	(1,004)
Net income (loss)									(36,884)	(35,277)	(34,760)
Net loss (income) attributable to noncontrolling interests									0	0	0
Net income attributable to Acadia									(36,884)	(35,277)	(34,760)
Real estate at cost	0				0				0	0
Total Assets	$ 0				$ 0				0	0
Cash paid for acquisition of real estate and leasehold interest									0
Cash paid for acquisition of real estate										0	0
Cash paid for development and property improvement costs									$ 0	$ 0	$ 0