XML 100 R84.htm IDEA: XBRL DOCUMENT v3.3.1.900

Related Party Transactions (Details) - Prior Owner - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Other Liabilities
Related Party Transactions
Investment partnerships with prior owners	$ 75.0	$ 71.6
Non-Controlling Interests
Related Party Transactions
Investment partnerships with prior owners	$ 5.1	$ 13.5

X

- Definition

Investment Partnerships with Prior Owners

+ References

No definition available.

+ Details

Name:	amg_InvestmentPartnershipswithPriorOwners
Namespace Prefix:	amg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

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

X

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=amg_PriorOwnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_NoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: