Segment Reporting (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) segment	Jun. 30, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			3
Revenues	$ 63,569	$ 59,504	$ 126,693	$ 121,503
Depreciation and amortization	(29,503)	(26,057)	(58,079)	(50,593)
Property operating expenses, other operating and real estate taxes	(19,860)	(17,841)	(39,237)	(36,938)
General and administrative expenses	(7,907)	(8,864)	(16,377)	(17,333)
Operating income	6,299	6,742	13,000	16,639
Gain on disposition of properties, net of tax	33	0	33	0
Interest income	3,289	8,203	7,026	17,187
Equity in earnings (losses) of unconsolidated affiliates	5,019	4,340	6,703	17,043
Interest expense	(16,915)	(12,750)	(32,805)	(24,238)
Income tax benefit (provision)	5	(427)	(387)	(552)
Net (loss) income	(2,270)	6,108	(6,430)	26,079
Net loss attributable to noncontrolling interests	9,935	5,952	21,514	1,612
Net income attributable to Acadia	7,665	12,060	15,084	27,691
Real estate at cost	3,548,043	3,486,007	3,548,043	3,486,007
Total assets	3,880,768	4,048,845	3,880,768	4,048,845
Cash paid for acquisition of real estate			46,171	77,785
Cash paid for development and property improvement costs			41,937	46,303
Operating segments | Core Portfolio
Segment Reporting Information [Line Items]
Revenues	40,539	41,488	82,166	85,933
Depreciation and amortization	(14,927)	(15,534)	(30,425)	(31,973)
Property operating expenses, other operating and real estate taxes	(10,510)	(10,160)	(21,405)	(23,012)
General and administrative expenses	0	0	0	0
Operating income	15,102	15,794	30,336	30,948
Gain on disposition of properties, net of tax	0		0
Interest income	0	0	0	0
Equity in earnings (losses) of unconsolidated affiliates	1,726	982	3,152	1,542
Interest expense	(7,001)	(6,933)	(13,502)	(14,088)
Income tax benefit (provision)	0	0	0	0
Net (loss) income	9,827	9,843	19,986	18,402
Net loss attributable to noncontrolling interests	200	(372)	128	(804)
Net income attributable to Acadia	10,027	9,471	20,114	17,598
Real estate at cost	2,047,672	1,984,601	2,047,672	1,984,601
Total assets	2,236,405	2,252,390	2,236,405	2,252,390
Cash paid for acquisition of real estate			1,343	0
Cash paid for development and property improvement costs			15,293	3,753
Operating segments | Funds
Segment Reporting Information [Line Items]
Revenues	23,030	18,016	44,527	35,570
Depreciation and amortization	(14,576)	(10,523)	(27,654)	(18,620)
Property operating expenses, other operating and real estate taxes	(9,350)	(7,681)	(17,832)	(13,926)
General and administrative expenses	0	0	0	0
Operating income	(896)	(188)	(959)	3,024
Gain on disposition of properties, net of tax	33		33
Interest income	0	0	0	0
Equity in earnings (losses) of unconsolidated affiliates	3,293	3,358	3,551	15,501
Interest expense	(9,914)	(5,817)	(19,303)	(10,150)
Income tax benefit (provision)	0	0	0	0
Net (loss) income	(7,484)	(2,647)	(16,678)	8,375
Net loss attributable to noncontrolling interests	9,735	6,324	21,386	2,416
Net income attributable to Acadia	2,251	3,677	4,708	10,791
Real estate at cost	1,500,371	1,501,406	1,500,371	1,501,406
Total assets	1,535,154	1,546,607	1,535,154	1,546,607
Cash paid for acquisition of real estate			44,828	77,785
Cash paid for development and property improvement costs			26,644	42,550
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
Operating income	0	0	0	0
Gain on disposition of properties, net of tax	0		0
Interest income	3,289	8,203	7,026	17,187
Equity in earnings (losses) of unconsolidated affiliates	0	0	0	0
Interest expense	0	0	0	0
Income tax benefit (provision)	0	0	0	0
Net (loss) income	3,289	8,203	7,026	17,187
Net loss attributable to noncontrolling interests	0	0	0	0
Net income attributable to Acadia	3,289	8,203	7,026	17,187
Real estate at cost	0	0	0	0
Total assets	109,209	249,848	109,209	249,848
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	(7,907)	(8,864)	(16,377)	(17,333)
Operating income	(7,907)	(8,864)	(16,377)	(17,333)
Gain on disposition of properties, net of tax	0		0
Interest income	0	0	0	0
Equity in earnings (losses) of unconsolidated affiliates	0	0	0	0
Interest expense	0	0	0	0
Income tax benefit (provision)	5	(427)	(387)	(552)
Net (loss) income	(7,902)	(9,291)	(16,764)	(17,885)
Net loss attributable to noncontrolling interests	0	0	0	0
Net income attributable to Acadia	(7,902)	(9,291)	(16,764)	(17,885)
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