XML 96 R80.htm IDEA: XBRL DOCUMENT v2.4.1.9

Goodwill and Acquired Client Relationships (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Goodwill
Asset impairment charges	$ 0us-gaap_AssetImpairmentCharges	$ 0us-gaap_AssetImpairmentCharges
Acquired Client Relationships
Goodwill
Weighted average life	10 years
Future annual amortization expense	$ 120,000,000amg_FiniteLivedIntangibleAssetsFutureAnnualAmortizationExpense / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember
Number of future annual periods of amortization expense presented	5 years

X

- Definition

The annual estimated amortization expense for succeeding fiscal years for intangible assets subject to amortization.

+ References

No definition available.

+ Details

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Namespace Prefix:	amg_
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Balance Type:	debit
Period Type:	duration

X

- Definition

The number of annual periods annual amortization expense is presented.

+ References

No definition available.

+ Details

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Namespace Prefix:	amg_
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X

- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2420-110228

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

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- Details

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