XML 55 R42.htm IDEA: XBRL DOCUMENT v3.8.0.1

Commitments and Contingencies (Details) - USD ($)	Dec. 31, 2018	Mar. 31, 2018
Commitments and Contingencies
Co-investment commitments in partnership		$ 120,400,000
Consolidated Affiliates
Commitments and Contingencies
Contingent liability		18,200,000
Expected payments of contingent liability		10,200,000
Present value of expected payments of contingent liabilities		9,800,000
Consolidated Affiliates | Scenario, Forecast
Commitments and Contingencies
Expected payments of contingent liability	$ 8,200,000
Equity Method Investee
Commitments and Contingencies
Contingent liability		$ 170,000,000
Equity Method Investee | Scenario, Forecast
Commitments and Contingencies
Expected payments of contingent liability	$ 0

X

- Definition

-- None. No documentation exists for this element. --

+ References

No definition available.

+ Details

Name:	amg_CommitmentAndContingenciesLineItems
Namespace Prefix:	amg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount that the entity agreed to co-invest in certain investment partnerships where the entity serves as the general partner.

+ References

No definition available.

+ Details

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

X

- Definition

Other Commitment Expected Payments

+ References

No definition available.

+ Details

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

X

- Definition

Other Commitment Present Value of Expected Payments

+ References

No definition available.

+ Details

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

X

- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

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

X

- Details

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

X

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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