Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Income from continuing operations									$ 72,776	$ 65,708	$ 70,865
Less: net income attributable to participating securities									(793)	(927)	(1,152)
Income from continuing operations net of income attributable to participating securities									$ 71,983	$ 64,781	$ 69,713
Denominator:
Weighted average shares for basic earnings per share									76,231,000	68,851,000	59,402,000
Effect of dilutive securities:
Employee share options									13,000	19,000	24,000
Denominator for diluted earnings per share	82,728,000	78,624,000	72,896,000	71,215,000	69,330,000	68,957,000	68,870,000	68,360,000	76,244,000	68,870,000	59,426,000
Basic earnings per Common Share from continuing operations attributable to Acadia (in dollars per share)									$ 0.94	$ 0.94	$ 1.18
Diluted earnings per Common Share from continuing operations attributable to Acadia (in dollars per share)									$ 0.94	$ 0.94	$ 1.18
Series A Preferred Stock [Member] | Common Shares
Schedule of Earnings Per Share, Basic and Diluted [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)									25,067	25,067	25,067
Series C Preferred Stock [Member]
Schedule of Earnings Per Share, Basic and Diluted [Line Items]
Preferred OP Units (in shares)	141,593								141,593
Series C Preferred Stock [Member] | Common Shares
Schedule of Earnings Per Share, Basic and Diluted [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)									407,845
Operating Partnership, as General Partner or Managing Member [Member]
Schedule of Earnings Per Share, Basic and Diluted [Line Items]
Preferred OP Units (in shares)	3,365,668				2,931,198				3,365,668	2,931,198
Operating Partnership, as General Partner or Managing Member [Member] | Series A Preferred Stock [Member]
Schedule of Earnings Per Share, Basic and Diluted [Line Items]
Preferred OP Units (in shares)	188				188				188	188	188
Operating Partnership, as General Partner or Managing Member [Member] | Series C Preferred Stock [Member]
Schedule of Earnings Per Share, Basic and Diluted [Line Items]
Preferred OP Units (in shares)		141,593