Cash to balance sheet after term loan repayments.

No definition available.

Name:	achc_CashToBalanceSheetAfterTermLoanRepayments
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt instrument transaction costs.

+ References

No definition available.

+ Details

Name:	achc_DebtInstrumentTransactionCosts
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Divestiture cash retained by buyer.

+ References

No definition available.

+ Details

Name:	achc_DivestitureCashRetainedByBuyer
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net proceeds from divestiture of businesses after deducting cash retained by buyer.

+ References

No definition available.

+ Details

Name:	achc_NetProceedsFromDivestitureOfBusinessesAfterDeductingCashRetainedByBuyer
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net proceeds from divestiture of businesses before cash retained by buyer.

+ References

No definition available.

+ Details

Name:	achc_NetProceedsFromDivestitureOfBusinessesBeforeCashRetainedByBuyer
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Payment of debt breakage costs.

+ References

No definition available.

+ Details

Name:	achc_PaymentOfDebtBreakageCosts
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Transaction costs related to sale of Business.

+ References

No definition available.

+ Details

Name:	achc_TransactionCostsRelatedToSaleOfBusiness
Namespace Prefix:	achc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value of all liability derivatives designated as cash flow hedging instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959

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

- Definition

Contractual interest rate for funds borrowed, under the debt 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

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

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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

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585

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

- Definition

The cash inflow from amounts received from issuance of long-term debt that is wholly or partially secured by collateral. Excludes proceeds from tax exempt secured debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

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

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

+ References

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

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-Name Accounting Standards Codification
-Topic 942
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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Period Type:	duration

- Details

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- Details

Name:	us-gaap_CreditFacilityAxis=achc_TermLoanAFacilityMember
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Period Type:

- Details

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- Details

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- Details

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- Details

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Subsequent Events - Additional Information (Detail) - USD ($)	Jan. 29, 2021	Jan. 19, 2021	Jan. 05, 2021
Tranche B-4 Facilities [Member]
Subsequent Event [Line Items]
Repayments of debt		$ 767,900,000	$ 105,000,000.0
Term Loan A- Facility [Member]
Subsequent Event [Line Items]
Repayments of debt		311,700,000
Subsequent Event [Member] \| Redemption of 5.265% Senior Notes [Member]
Subsequent Event [Line Items]
Senior Notes	$ 650,000,000
Debt instrument interest rate	5.265%
Subsequent Event [Member] \| Redemption of 6.500% Senior Notes [Member]
Subsequent Event [Line Items]
Senior Notes	$ 390,000,000
Debt instrument interest rate	6.50%
Subsequent Event [Member] \| Redemption of 5.265% Senior Notes and 6.500% Senior Notes [Member]
Subsequent Event [Line Items]
Debt instrument, redemption date	Jan. 29, 2021
Senior Notes	$ 1,040,000,000
Payment of breakage costs	6,000,000
Estimated transaction costs	9,000,000
Debt instrument funded from cash	430,000,000
Proceeds from new senior secured credit facility	$ 625,000,000
Debt instrument term	5 years
Discontinued Operations [Member] \| U.K. Sales [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Gross proceeds from sale of business		1,525,000,000
Cash retained by buyer		75,000,000
Transaction costs		16,000,000
Settlement of existing foreign currency hedging liabilities		85,000,000
Net proceeds from sale of business		1,425,000,000
Net proceeds from sale of business, after deducting cash retained by buyer		1,350,000,000
Cash		345,000,000
Discontinued Operations [Member] \| U.K. Sales [Member] \| Subsequent Event [Member] \| Tranche B-4 Facilities [Member]
Subsequent Event [Line Items]
Repayments of debt		768,000,000
Discontinued Operations [Member] \| U.K. Sales [Member] \| Subsequent Event [Member] \| Term Loan A- Facility [Member]
Subsequent Event [Line Items]
Repayments of debt		$ 312,000,000