Federal Income Taxes - Reconciliation of Net Income to Taxable Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Net income attributable to Acadia	$ 20,912	$ 12,867	$ 12,060	$ 15,631	$ 19,821	$ 6,112	$ 17,918	$ 28,925	$ 61,470	$ 72,776	$ 65,708
Deferred cancellation of indebtedness income									2,050	2,050	2,050
Deferred rental and other income									(934)	1,610	82
Book/tax difference - depreciation and amortization									21,334	15,189	9,983
Straight-line rent and above- and below-market rent adjustments									(10,559)	(7,882)	(8,041)
Book/tax differences - equity-based compensation									5,325	10,307	5,833
Joint venture equity in earnings, net									9,114	(2,011)	5,776
Impairment charges and reserves									0	769	(714)
Acquisition costs									1,135	5,116	1,190
Gains									(5,181)	0	(760)
Book/tax differences - miscellaneous									930	(4,924)	2,573
Taxable income									84,684	93,000	83,680
Distributions declared									$ 87,848	$ 91,053	$ 84,683