XML 55 R42.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Debt (Details) - USD ($) | Jun. 30, 2016 | May 31, 2016
--- | --- | ---
Senior Unsecured Revolving Credit Facility |  |
Debt Instrument |  |
Maximum borrowing capacity | $ 1,450,000,000 | $ 1,300,000,000
Maximum borrowing capacity, additional amount | 350,000,000.0 |
Senior Unsecured Term Loan |  |
Debt Instrument |  |
Principal Amount at Maturity | 385,000,000 | $ 350,000,000
Maximum borrowing capacity, additional amount | $ 65,000,000.0 |

X
- Definition Debt Instrument, Maximum Borrowing Capacity, Additional Amount + References No definition available. + Details
Name: | amg_DebtInstrumentMaximumBorrowingCapacityAdditionalAmount
Namespace Prefix: | amg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=amg_SeniorUnsecuredCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=amg_SeniorUnsecuredTermLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |