Expected Proceeds from Sale of Property Held-for-sale

No definition available.

Name:	amh_ExpectedProceedsfromSaleofPropertyHeldforsale
Namespace Prefix:	amh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of Real Estate Properties Held-for-Sale in Escrow

+ References

No definition available.

+ Details

Name:	amh_NumberofRealEstatePropertiesHeldforSaleinEscrow
Namespace Prefix:	amh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248

+ Details

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

- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_LongTermPurchaseCommitmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=amh_SilverBayRealtyTrustCorp.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=srt_SingleFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=us-gaap_LandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=amh_CommitmentToAcquirePropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_SuretyBondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies (Details) $ in Millions	9 Months Ended	12 Months Ended
Commitments and Contingencies (Details) $ in Millions	Sep. 30, 2019 USD ($) property	Dec. 31, 2018 USD ($) property	Dec. 31, 2017 USD ($)
Purchase Commitment [Line Items]
Single-family properties sales in escrow \| property	288	78
Single-family properties sales in escrow, selling price	$ 51.9	$ 13.6
Silver Bay Realty Trust Corp.
Gain (Loss) on Sale of Securities, Net [Abstract]
Gain (loss) on sale of equity investments			$ 3.0
Single Family Properties
Purchase Commitment [Line Items]
Purchase price of commitment to acquire single-family properties	3.5	25.3
Land
Purchase Commitment [Line Items]
Purchase price of commitment to acquire single-family properties	$ 65.3	$ 58.1
Commitment To Acquire Properties
Purchase Commitment [Line Items]
Number of properties \| property	13	88
Surety bond
Purchase Commitment [Line Items]
Surety bonds related to development contracts	$ 9.9	$ 5.1