Restatement of Previously Issued Consolidated Financial Statements - Schedule of Condensed Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended							6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements, Captions [Line Items]
Revenues												$ 292,497	$ 250,908	$ 289,585
Operating expenses
Depreciation and amortization												123,439	147,229	122,580
General and administrative												40,125	35,798	34,299
Real estate taxes												45,357	42,477	38,333
Property operating												53,516	55,551	49,898
Impairment charges												9,925	85,598	1,721
Total operating expenses												272,362	366,653	246,831
Gain on disposition of properties												10,521	683	30,324
Operating income												30,656	(115,062)	73,078
Equity in earnings of unconsolidated affiliates												5,330	(3,057)	5,899
Interest and other income												9,065	8,979	7,988
Realized and unrealized holding gains on investments and other												49,120	113,362	6,947
Interest expense												(68,048)	(69,671)	(69,213)
Income (loss) from continuing operations before income taxes												26,123	(65,449)	24,699
Income tax provision												(93)	(269)	(1,465)
Net income (loss)												26,030	(65,718)	23,234
Net (income) loss attributable to noncontrolling interests												2,482	(56,742)	(30,483)
Net income (loss) attributable to Acadia												23,548	(8,976)	53,717
Net income attributable to participating securities												624	233	413
Shares for basic and diluted income per share							86,972,000
Rental Income
Condensed Income Statements, Captions [Line Items]
Revenues												285,898	246,432	285,470
Other
Condensed Income Statements, Captions [Line Items]
Revenues												$ 6,599	4,476	4,115
Previously Reported
Condensed Income Statements, Captions [Line Items]
Revenues	$ 73,446	$ 74,660	$ 69,394	$ 69,010	$ 51,281		$ 71,420	$ 144,054		$ 217,500	$ 186,474		255,484	295,327
Operating expenses
Depreciation and amortization	30,866	31,345	31,390	48,166	34,457	$ 33,793	33,377	62,735	$ 67,170	93,601	101,627		149,793	125,443
General and administrative	9,978	10,671	8,996	9,640	8,625	8,720	9,070	19,667	17,790	29,645	26,415		36,055	35,416
Real estate taxes	11,320	12,504	11,462	11,672	10,689	10,697	10,447	23,966	21,144	35,286	31,833		43,505	39,315
Property operating	12,698	12,890	13,477	14,910	11,559	16,806	13,320	26,367	30,126	39,065	41,685		56,595	51,153
Impairment charges	9,925	0	0	34,049		0	51,549	0	51,549	9,925	51,549		85,598	1,721
Total operating expenses	74,787	67,410	65,325	118,437	65,330	70,016	117,763	132,735	187,779	207,522	253,109		371,546	253,048
Gain on disposition of properties		5,909	4,612	174	24	485	0	10,521	485	10,521	509		683	30,324
Operating income	(1,341)	13,159	8,681	(49,253)	(14,025)	(5,758)	(46,343)	21,840	(52,101)	20,499	(66,126)		(115,379)	72,603
Equity in earnings of unconsolidated affiliates	644	1,106	2,263	(1,082)	(624)	(786)	1,255	3,369	469	4,013	(155)		(1,237)	8,922
Interest and other income													8,979	7,988
Realized and unrealized holding gains on investments and other	47,293	2,711	6,507	34,595	(7,946)	87,811	(530)	9,218	87,281	56,511	79,335		113,930	6,947
Interest expense	(17,334)	(17,605)	(17,141)	(17,687)	(17,752)	(18,319)	(18,302)	(34,746)	(36,621)	(52,080)	(54,373)		(72,060)	(73,788)
Income (loss) from continuing operations before income taxes	31,616	1,425	2,010	(31,604)	(38,215)	65,043	(60,991)	3,435	4,052	35,051	(34,163)		(65,767)	22,672
Income tax provision	(59)	(194)	(150)	(1,012)	(74)	(137)	952	(344)	815	(403)	741		(271)	(1,468)
Net income (loss)	31,557	1,231	1,860	(32,616)	(38,289)	64,906	(60,039)	3,091	4,867	34,648	(33,422)		(66,038)	21,204
Net (income) loss attributable to noncontrolling interests	(19,488)	2,687	3,302	21,891	29,259	(45,496)	51,625	5,989	6,129	(13,499)	35,388		57,279	31,841
Net income (loss) attributable to Acadia	12,069	3,918	5,162	(10,725)	(9,030)	19,410	(8,414)	9,080	10,996	21,149	1,966		(8,759)	53,045
Net income attributable to participating securities	$ 156	$ 156	$ 156	$ 0		$ 244		$ 312	$ 233	$ 468	$ 233		$ 233	$ 413
Shares for basic and diluted income per share	88,481	86,824	86,346	86,311,000	86,309	86,180	86,972,000	86,575	86,576	87,217	86,486		86,442	84,436
Basic loss per shares				$ (0.12)	$ (0.10)		$ (0.10)				$ 0.02		$ (0.10)	$ 0.62
Previously Reported | Rental Income
Condensed Income Statements, Captions [Line Items]
Revenues	$ 71,852	$ 73,666	$ 67,205	$ 67,606	$ 50,300	$ 62,639	$ 70,457	$ 140,871	$ 133,096	$ 212,723	$ 183,396		$ 251,002	$ 291,190
Previously Reported | Other
Condensed Income Statements, Captions [Line Items]
Revenues	1,594	994	2,189	1,404	981	1,134	963	3,183	2,097	4,777	3,078		4,482	4,137
Adjustments
Condensed Income Statements, Captions [Line Items]
Revenues	(1,550)	(1,603)	(1,207)	(1,132)	(890)		675	(2,810)		(4,360)	(3,444)		(4,576)	(5,742)
Operating expenses
Depreciation and amortization	(802)	(805)	(750)	(722)	(697)	(416)	(729)	(1,555)	(1,145)	(2,357)	(1,842)		(2,564)	(2,863)
General and administrative	(68)	(18)	(4)	0	(210)	(38)	(9)	(22)	(47)	(90)	(257)		(257)	(1,117)
Real estate taxes	(292)	(290)	(256)	(263)	(261)	(252)	(252)	(546)	(504)	(838)	(765)		(1,028)	(982)
Property operating	(255)	(254)	(268)	(306)	(210)	(245)	(283)	(522)	(528)	(777)	(738)		(1,044)	(1,255)
Impairment charges		0	0	0		0	0	0	0		0		0	0
Total operating expenses	(1,417)	(1,367)	(1,278)	(1,291)	(1,378)	(951)	(1,273)	(2,645)	(2,224)	(4,062)	(3,602)		(4,893)	(6,217)
Gain on disposition of properties				0			0						0	0
Operating income	(133)	(236)	71	159	488	(2,278)	1,948	(165)	(330)	(298)	158		317	475
Equity in earnings of unconsolidated affiliates	(272)	(207)	(381)	(446)	(612)	(394)	(368)	(588)	(762)	(860)	(1,374)		(1,820)	(3,023)
Interest and other income													0	0
Realized and unrealized holding gains on investments and other	(800)	(869)	(1,382)	(568)				(2,251)		(3,051)			(568)	0
Interest expense	720	531	527	546	570	571	702	1,058	1,273	1,778	1,843		2,389	4,575
Income (loss) from continuing operations before income taxes	(485)	(781)	(1,165)	(309)	446	(2,101)	2,282	(1,946)	181	(2,431)	627		318	2,027
Income tax provision		2	2	0			2	4	2	4	2		2	3
Net income (loss)	(485)	(779)	(1,163)	(309)	446	(2,101)	2,284	(1,942)	183	(2,427)	629		320	2,030
Net (income) loss attributable to noncontrolling interests	423	572	818	172	(451)	2,017	(2,275)	1,390	(258)	1,813	(709)		(537)	(1,358)
Net income (loss) attributable to Acadia	(62)	(207)	(345)	(137)	(5)	(84)	9	(552)	(75)	(614)	(80)		(217)	672
Net income attributable to participating securities			$ 0	$ 0									$ 0	$ 0
Shares for basic and diluted income per share			0		0								0	0
Basic loss per shares				$ (0.01)									$ (0.01)	$ 0.01
Adjustments | Rental Income
Condensed Income Statements, Captions [Line Items]
Revenues	$ (1,550)	$ (1,597)	$ (1,207)	$ (1,138)	$ (890)	$ (3,218)	$ 676	$ (2,804)	$ (2,542)	$ (4,354)	$ (3,432)		$ (4,570)	$ (5,720)
Adjustments | Other
Condensed Income Statements, Captions [Line Items]
Revenues		(6)	0	6		(11)	(1)	(6)	(12)	(6)	(12)		(6)	(22)
As Restated
Condensed Income Statements, Captions [Line Items]
Revenues	71,896	73,057	68,187	67,878	50,391		72,095	141,244		213,140	183,030		250,908	289,585
Operating expenses
Depreciation and amortization	30,064	30,540	30,640	47,444	33,760	33,377	32,648	61,180	66,025	91,244	99,785		147,229	122,580
General and administrative	9,910	10,653	8,992	9,640	8,415	8,682	9,061	19,645	17,743	29,555	26,158		35,798	34,299
Real estate taxes	11,028	12,214	11,206	11,409	10,428	10,445	10,195	23,420	20,640	34,448	31,068		42,477	38,333
Property operating	12,443	12,636	13,209	14,604	11,349	16,561	13,037	25,845	29,598	38,288	40,947		55,551	49,898
Impairment charges	9,925	0	0	34,049		0	51,549	0	51,549	9,925	51,549		85,598	1,721
Total operating expenses	73,370	66,043	64,047	117,146	63,952	69,065	116,490	130,090	185,555	203,460	249,507		366,653	246,831
Gain on disposition of properties		5,909	4,612	174	24	485	0	10,521	485	10,521	509		683	30,324
Operating income	(1,474)	12,923	8,752	(49,094)	(13,537)	(8,036)	(44,395)	21,675	(52,431)	20,201	(65,968)		(115,062)	73,078
Equity in earnings of unconsolidated affiliates	372	899	1,882	(1,528)	(1,236)	(1,180)	887	2,781	(293)	3,153	(1,529)		(3,057)	5,899
Interest and other income													8,979	7,988
Realized and unrealized holding gains on investments and other	46,493	1,842	5,125	34,027	(7,946)	87,811	(530)	6,967	87,281	53,460	79,335		113,362	6,947
Interest expense	(16,614)	(17,074)	(16,614)	(17,141)	(17,182)	(17,748)	(17,600)	(33,688)	(35,348)	(50,302)	(52,530)		(69,671)	(69,213)
Income (loss) from continuing operations before income taxes	31,131	644	845	(31,913)	(37,769)	62,942	(58,709)	1,489	4,233	32,620	(33,536)		(65,449)	24,699
Income tax provision	(59)	(192)	(148)	(1,012)	(74)	(137)	954	(340)	817	(399)	743		(269)	(1,465)
Net income (loss)	31,072	452	697	(32,925)	(37,843)	62,805	(57,755)	1,149	5,050	32,221	(32,793)		(65,718)	23,234
Net (income) loss attributable to noncontrolling interests	(19,065)	3,259	4,120	22,063	28,808	(43,479)	49,350	7,379	5,871	(11,686)	34,679		56,742	30,483
Net income (loss) attributable to Acadia	12,007	3,711	4,817	(10,862)	(9,035)	19,326	(8,405)	8,528	10,921	20,535	1,886		(8,976)	53,717
Net income attributable to participating securities	$ 156	$ 156	$ 156	$ 0		$ 244		$ 312	$ 233	$ 468	$ 233		$ 233	$ 413
Shares for basic and diluted income per share	88,481	86,824	86,346	86,311,000	86,309	86,180		86,575	86,576	87,217	86,486		86,442	84,436
Basic loss per shares				$ (0.13)	$ (0.10)		$ (0.10)				$ 0.02		$ (0.11)	$ 0.63
As Restated | Rental Income
Condensed Income Statements, Captions [Line Items]
Revenues	$ 70,302	$ 72,069	$ 65,998	$ 66,468	$ 49,410	$ 59,421	$ 71,133	$ 138,067	$ 130,554	$ 208,369	$ 179,964		$ 246,432	$ 285,470
As Restated | Other
Condensed Income Statements, Captions [Line Items]
Revenues	$ 1,594	$ 988	$ 2,189	$ 1,410	$ 981	$ 1,123	$ 962	$ 3,177	$ 2,085	$ 4,771	$ 3,066		$ 4,476	$ 4,115