The number of units of the operating partnership owned by the noncontrolling interest, a related party.

No definition available.

Name:	amh_NoncontrollingInterestUnitsOwnedInOperatingPartnership
Namespace Prefix:	amh_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_CapitalUnitLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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

Amount of Net Income (Loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1A

-URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4J

-URI http://asc.fasb.org/extlink&oid=31814832&loc=SL4591551-111686

+ Details

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

- Definition

The number of each class of partnership units outstanding at the balance sheet date. Units represent shares of ownership of the general, limited, and preferred partners.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.6-04.16(a))

-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 5

-Subparagraph (SAB TOPIC 4.F)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 16

-Subparagraph a, b

-Article 6

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.6-04.16(b))

-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996

+ Details

Name:	us-gaap_PartnersCapitalAccountUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Shareholders' equity (Details 2) (USD $) In Millions, except Share data, unless otherwise specified			3 Months Ended	9 Months Ended				3 Months Ended		9 Months Ended						3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014 Sponsor	Dec. 31, 2013 Sponsor	Sep. 30, 2014 Operating Partnership Class A Units	Sep. 30, 2014 Operating Partnership Class A Units	Dec. 31, 2013 Operating Partnership Class A Units	Sep. 30, 2014 Operating Partnership Class A Units Sponsor	Dec. 31, 2013 Operating Partnership Class A Units Sponsor	Sep. 30, 2014 Operating Partnership Series C Convertible Units	Sep. 30, 2013 Operating Partnership Series C Convertible Units	Sep. 30, 2014 Operating Partnership Series C Convertible Units	Sep. 30, 2013 Operating Partnership Series C Convertible Units	Sep. 30, 2014 Operating Partnership Series C Convertible Units Sponsor	Dec. 31, 2013 Operating Partnership Series C Convertible Units Sponsor	Sep. 30, 2014 Operating Partnership Series D Convertible Units Sponsor	Dec. 31, 2013 Operating Partnership Series D Convertible Units Sponsor	Sep. 30, 2014 Certain consolidated subsidiaries with noncontrolling interest	Sep. 30, 2013 Certain consolidated subsidiaries with noncontrolling interest	Sep. 30, 2014 Certain consolidated subsidiaries with noncontrolling interest	Sep. 30, 2013 Certain consolidated subsidiaries with noncontrolling interest	Sep. 30, 2013 Certain consolidated subsidiaries with noncontrolling interest Preferred Units	Sep. 30, 2013 Certain consolidated subsidiaries with noncontrolling interest Preferred Units	Sep. 30, 2013 Certain consolidated subsidiaries with noncontrolling interest Class A Units	Sep. 30, 2013 Certain consolidated subsidiaries with noncontrolling interest Class A Units
Class of Stock
Percentage of units outstanding	21.70%	24.60%				6.10%	6.90%
Units owned (in shares)						13,787,292	13,787,292					31,085,974	31,085,974	4,375,000	4,375,000
Units outstanding (in shares)			225,261,198	225,261,198	199,291,586
Income (loss) allocated to noncontrolling interest			$ (1.1)	$ (2.5)				$ 4.7	$ 4.7	$ 13.9	$ 10.2					$ (0.2)	$ (0.2)	$ (0.2)	$ (0.2)	$ 0	$ 0.2	$ (0.7)	$ (0.8)