XML 127 R107.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Income Taxes - Schedule of reconciliation of beginning and ending amount of unrecognized tax benefits (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Reconciliation of beginning and ending amount of unrecognized tax benefits |  |  |
Beginning balance | $ 22.6 | $ 21.2 | $ 24.6
Additions based on current year tax positions | 4.1 | 5.9 | 4.8
Additions based on prior years' tax positions | 0 | 5.2 | 0
Reductions for prior years' tax provisions | (0.1) | (5.4) | 0
Settlements | 0 | 0 | (1.2)
Reductions related to lapses of statutes of limitations | (5.4) | (4.6) | (6.7)
Additions (reductions) related to foreign exchange rates | (0.8) | 0.3 | (0.3)
Ending balance | $ 20.4 | $ 22.6 | $ 21.2

X
- Definition The gross amount of additions (reductions) related to foreign exchange rates resulting from settlements with taxing authorities. + References No definition available. + Details
Name: | amg_UnrecognizedTaxBenefitsRelatedToForeignExchangeRates
Namespace Prefix: | amg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Unrecognized Tax Benefit -URI http://asc.fasb.org/extlink&oid=6527854 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration