Business combination working capital settlement.

No definition available.

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

- Definition

The number of licensed beds acquired at the entities as of the acquisition date.

+ References

No definition available.

+ Details

Name:	achc_NumberOfAcquiredBeds
Namespace Prefix:	achc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of facilities acquired during the period stated.

+ References

No definition available.

+ Details

Name:	achc_NumberOfFacilitiesAcquired
Namespace Prefix:	achc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of inpatient facilities.

+ References

No definition available.

+ Details

Name:	achc_NumberOfInpatientFacilities
Namespace Prefix:	achc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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Data Type:	xbrli:sharesItemType
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

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

+ Details

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

- Definition

This element represents the fair value of the noncontrolling interest in the acquiree at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

+ Details

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

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
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-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

+ Details

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

- Definition

Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 5
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+ Details

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

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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-Publisher FASB
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-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

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

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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Acquisitions - 2015 US Acquisitions - Additional Information (Detail) $ in Millions	Dec. 01, 2015 USD ($) Beds Facility	Nov. 01, 2015 USD ($) State Beds Center	Jul. 01, 2015 USD ($) Beds	Mar. 01, 2015 USD ($) Center	Feb. 11, 2015 USD ($) State Beds Center Facilities shares	Jun. 30, 2016 State	Aug. 31, 2015 USD ($)
Business Acquisition [Line Items]
Number of operating states \| State						39
MMO Behavioral Health Systems [Member]
Business Acquisition [Line Items]
Number of beds \| Beds	80
Business acquisition cash paid	$ 20.2
Number of facilities acquired \| Facility	2
Discovery House-Group Inc [Member]
Business Acquisition [Line Items]
Business acquisition cash paid		$ 118.3
Number of facilities acquired \| Center		19
Number of operating states \| State		4
Duffys Napa Valley Rehab [Member]
Business Acquisition [Line Items]
Number of beds \| Beds		61
Business acquisition cash paid		$ 29.6
Quality Addiction Management [Member]
Business Acquisition [Line Items]
Business acquisition cash paid				$ 54.8
Number of facilities acquired \| Center				7
CRC Health Group, Inc [Member]
Business Acquisition [Line Items]
Number of facilities acquired \| Center					81
Number of operating states \| State					30
Total consideration related to acquisition					$ 1,300.0
Shares issued for acquisition \| shares					5,975,326
Outstanding indebtedness of CRC repaid					$ 904.5
Number of inpatient facilities \| Facilities					35
CRC Health Group, Inc [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Number of beds \| Beds					2,400
Massachusetts [Member] \| Southcoast Behavioral [Member]
Business Acquisition [Line Items]
Approximate value of noncontrolling interest							$ 9.2
Equity ownership interests percentage in the facility							75.00%
Percentage of noncontrolling interests in the facility							25.00%
Pennsylvania [Member] \| Belmont Behavioral Health [Member]
Business Acquisition [Line Items]
Number of beds \| Beds			147
Business acquisition cash paid			$ 39.0
Total consideration related to acquisition			35.0
Working capital settlement			$ 4.0