XML 53 R116.htm IDEA: XBRL DOCUMENT v2.4.1.9

Segment Information (Details)	12 Months Ended
	Dec. 31, 2014 Channel Segment	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting [Abstract]
Number of operating segments	3us-gaap_NumberOfReportableSegments
Number of principal distribution channels	3amg_NumberOfPrincipalDistributionChannels
Revenue attributable to clients domiciled outside the United States (as a percent)	37.00%amg_PercentageOfRevenueFromExternalCustomersAttributedToForeignCountries	38.00%amg_PercentageOfRevenueFromExternalCustomersAttributedToForeignCountries	41.00%amg_PercentageOfRevenueFromExternalCustomersAttributedToForeignCountries

X

- Definition

Number of principal distribution channels.

+ References

No definition available.

+ Details

Name:	amg_NumberOfPrincipalDistributionChannels
Namespace Prefix:	amg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the percentage of total revenues from external customers attributed to foreign countries from which the entity derives revenues.

+ References

No definition available.

+ Details

Name:	amg_PercentageOfRevenueFromExternalCustomersAttributedToForeignCountries
Namespace Prefix:	amg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Details

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