Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net income attributable to Acadia	$ 12,060	$ 17,918	$ 27,691	$ 46,843
Less: net income attributable to participating securities	(126)	(223)	(372)	(589)
Income from continuing operations net of income attributable to participating securities	$ 11,934	$ 17,695	$ 27,319	$ 46,254
Denominator:
Weighted average shares for basic earnings per share	83,661,953	72,895,868	83,648,415	71,825,784
Effect of dilutive securities:
Employee unvested restricted shares	0	0	5,365	7,861
Convertible Preferred OP Units	0	0	0	25,067
Weighted Average Number of Shares Outstanding, Diluted	83,661,953	72,895,868	83,653,780	71,858,712
Basic and diluted earnings per Common Share from continuing operations attributable to Acadia	$ 0.14	$ 0.24	$ 0.33	$ 0.64
Series A Preferred OP Units
Anti-Dilutive Shares Excluded from Denominator:
Antidilutive securities excluded from computation of earnings per share (in shares)	188	188	188	0
Series A Preferred OP Units - Common share equivalent
Anti-Dilutive Shares Excluded from Denominator:
Antidilutive securities excluded from computation of earnings per share (in shares)	25,067	25,067	25,067	0
Series C Preferred OP Units
Anti-Dilutive Shares Excluded from Denominator:
Antidilutive securities excluded from computation of earnings per share (in shares)	140,343	141,593	140,343	141,593
Series C Preferred OP Units - Common share equivalent
Anti-Dilutive Shares Excluded from Denominator:
Antidilutive securities excluded from computation of earnings per share (in shares)	487,299	402,252	479,167	402,653
Restricted shares
Anti-Dilutive Shares Excluded from Denominator:
Antidilutive securities excluded from computation of earnings per share (in shares)	43,318	50,156	0	0