Condensed Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Earnings (Accumulated Deficit) [Member]
Balance at Dec. 31, 2018	$ 2,333,307	$ 874	$ 2,541,987	$ (462,377)	$ 252,823
Balance, shares at Dec. 31, 2018		87,444,000
Common stock issued under stock incentive plans	293	$ 2	291
Common stock issued under stock incentive plans, shares		149,000
Common stock withheld for minimum statutory taxes	(1,620)		(1,620)
Equity-based compensation expense	6,101		6,101
Other comprehensive income (loss)	35,791			35,791
Net income (loss) attributable to Acadia Healthcare Company, Inc.	29,471				29,471
Balance at Mar. 31, 2019	2,403,343	$ 876	2,546,759	(426,586)	282,294
Balance, shares at Mar. 31, 2019		87,593,000
Balance at Dec. 31, 2018	$ 2,333,307	$ 874	2,541,987	(462,377)	252,823
Balance, shares at Dec. 31, 2018		87,444,000
Common stock issued under stock incentive plans, shares	55,671
Balance at Dec. 31, 2019	$ 2,505,381	$ 877	2,557,642	(414,884)	361,746
Balance, shares at Dec. 31, 2019	87,715,591	87,715,000
Balance at Mar. 31, 2019	$ 2,403,343	$ 876	2,546,759	(426,586)	282,294
Balance, shares at Mar. 31, 2019		87,593,000
Common stock issued under stock incentive plans	68		68
Common stock issued under stock incentive plans, shares		52,000
Common stock withheld for minimum statutory taxes	(356)		(356)
Equity-based compensation expense	4,182		4,182
Other comprehensive income (loss)	(33,031)			(33,031)
Net income (loss) attributable to Acadia Healthcare Company, Inc.	48,140				48,140
Balance at Jun. 30, 2019	2,422,346	$ 876	2,550,653	(459,617)	330,434
Balance, shares at Jun. 30, 2019		87,645,000
Common stock issued under stock incentive plans	154	$ 1	153
Common stock issued under stock incentive plans, shares		10,000
Common stock withheld for minimum statutory taxes	(37)		(37)
Equity-based compensation expense	4,039		4,039
Other comprehensive income (loss)	(48,377)			(48,377)
Net income (loss) attributable to Acadia Healthcare Company, Inc.	42,566				42,566
Balance at Sep. 30, 2019	2,420,691	$ 877	2,554,808	(507,994)	373,000
Balance, shares at Sep. 30, 2019		87,655,000
Common stock issued under stock incentive plans	54		54
Common stock issued under stock incentive plans, shares		60,000
Common stock withheld for minimum statutory taxes	(205)		(205)
Equity-based compensation expense	2,985		2,985
Other comprehensive income (loss)	93,110			93,110
Net income (loss) attributable to Acadia Healthcare Company, Inc.	(11,254)				(11,254)
Balance at Dec. 31, 2019	$ 2,505,381	$ 877	2,557,642	(414,884)	361,746
Balance, shares at Dec. 31, 2019	87,715,591	87,715,000
Common stock issued under stock incentive plans		$ 1	(1)
Common stock issued under stock incentive plans, shares		127,000
Common stock withheld for minimum statutory taxes	$ (1,402)		(1,402)
Equity-based compensation expense	4,979		4,979
Other comprehensive income (loss)	(78,254)			(78,254)
Net income (loss) attributable to Acadia Healthcare Company, Inc.	33,463				33,463
Balance at Mar. 31, 2020	$ 2,464,167	$ 878	$ 2,561,218	$ (493,138)	$ 395,209
Balance, shares at Mar. 31, 2020	87,842,302	87,842