Consolidated senior secured net leverage ratio.

No definition available.

Name:	achc_ConsolidatedSeniorSecuredNetLeverageRatio
Namespace Prefix:	achc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Incremental debt amount maximum percentage of consolidated EBITDA.

+ References

No definition available.

+ Details

Name:	achc_IncrementalDebtAmountMaximumPercentageOfConsolidatedEBITDA
Namespace Prefix:	achc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum consolidated net leverage ratio.

+ References

No definition available.

+ Details

Name:	achc_MaximumConsolidatedNetLeverageRatio
Namespace Prefix:	achc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum incremental debt amount.

+ References

No definition available.

+ Details

Name:	achc_MaximumIncrementalDebtAmount
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum interest coverage ratio.

+ References

No definition available.

+ Details

Name:	achc_MinimumInterestCoverageRatio
Namespace Prefix:	achc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

End date of debt instrument redemption period, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodEndDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the credit facility first became available, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInitiationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Balance Type:
Period Type:

- Details

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Period Type:

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Period Type:

- Details

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Balance Type:
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
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Balance Type:
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=achc_SwinglineCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_StandbyLettersOfCreditMember
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Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=achc_AmendedAndRestatedCreditAgreementMember
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Long-Term Debt (New Credit Facility) - Additional Information (Detail) - USD ($)		3 Months Ended
	Mar. 17, 2021	Mar. 31, 2021	Nov. 13, 2020
Term Loan A- Facility [Member]
Debt Instrument [Line Items]
Line of credit outstanding principal amount			$ 352,400,000
New Credit Facility [Member]
Debt Instrument [Line Items]
Date entered into an agreement	Mar. 17, 2021
Term loan remaining balance due date		Mar. 31, 2026
Maximum incremental debt amount		$ 480,000,000.0
Incremental debt amount maximum percentage of consolidated EBITDA		100.00%
Consolidated senior secured net leverage ratio		350.00%
Maximum consolidated net leverage ratio		500.00%
Minimum interest coverage ratio		300.00%
New Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		1.75%
New Credit Facility [Member] \| Base Rate Loans [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.75%
New Credit Facility [Member] \| June 30, 2021 to March 31, 2022 [Member]
Debt Instrument [Line Items]
Term loan principal repayments		$ 2,700,000
New Credit Facility [Member] \| June 30, 2022 to March 31, 2024 [Member]
Debt Instrument [Line Items]
Term loan principal repayments		5,300,000
New Credit Facility [Member] \| June 30, 2024 to March 31, 2025 [Member]
Debt Instrument [Line Items]
Term loan principal repayments		8,000,000.0
New Credit Facility [Member] \| June 30, 2025 to December 31, 2025 [Member]
Debt Instrument [Line Items]
Term loan principal repayments		10,600,000
New Credit Facility [Member] \| Senior Secured Revolving Line of Credit [Member]
Debt Instrument [Line Items]
Line of credit outstanding principal amount	$ 600,000,000.0	160,000,000
Debt instrument maturity date	Mar. 17, 2026
Amount available under revolving line of credit		$ 422,000,000.0
Unused fee payable percentage		0.25%
New Credit Facility [Member] \| Term Loan A- Facility [Member]
Debt Instrument [Line Items]
Line of credit outstanding principal amount	$ 425,000,000.0	$ 425,000,000
Debt instrument maturity date	Mar. 17, 2026
New Credit Facility [Member] \| Letters of Credit [Member]
Debt Instrument [Line Items]
Line of credit outstanding principal amount	$ 20,000,000.0
New Credit Facility [Member] \| Swingline Facility [Member]
Debt Instrument [Line Items]
Line of credit outstanding principal amount	$ 20,000,000.0
New Credit Facility [Member] \| Standby Letters of Credit [Member]
Debt Instrument [Line Items]
Line of credit outstanding principal amount		$ 18,000,000.0
Amended and Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Agreement termination date	Mar. 17, 2021