Earnings Per Share - Summary of Elements Used in Calculating Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator - basic and diluted earnings per share
Net income									$ 86,762	$ 119,124	$ 70,121
Net (income) loss attributable to noncontrolling interests	$ (1,128)	$ 887	$ 176	$ (1,728)	$ (2,117)	$ 392	$ 19	$ (323)	(1,793)	(2,029)	(1,083)
Net income attributable to ACC, Inc. and Subsidiaries common stockholders	$ 24,720	$ 20,223	$ 10,386	$ 29,640	$ 47,504	$ (2,345)	$ 46,009	$ 25,927	84,969	117,095	69,038
Amount allocated to participating securities									(1,902)	(1,522)	(1,536)
Net income attributable to common stockholders									$ 83,067	$ 115,573	$ 67,502
Denominator
Basic weighted average common shares outstanding (shares)									137,295,837	136,815,051	135,141,423
Unvested restricted stock awards (shares)									990,941	906,998	860,962
Diluted weighted average common shares outstanding (shares)									138,286,778	137,722,049	136,002,385
Earnings per share
Net income (loss) attributable to common stockholders per share - basic (in dollars per share)	$ 0.18	$ 0.14	$ 0.07	$ 0.21	$ 0.34	$ (0.02)	$ 0.33	$ 0.19	$ 0.61	$ 0.84	$ 0.50
Net income (loss) attributable to common stockholders per share - diluted (in dollars per share)	$ 0.18	$ 0.14	$ 0.07	$ 0.21	$ 0.34	$ (0.02)	$ 0.33	$ 0.18	$ 0.60	$ 0.84	$ 0.50