XML 43 R30.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Equity Method Investments in Affiliates (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract] |
Schedule of Aggregate Purchase Price Allocation of Equity Method Investments | The aggregate purchase price allocation for the 2016 investments was as follows:
| Total
Consideration paid | $ | 1,362.3 |
Definite-lived acquired client relationships | $ | 560.8 |
Indefinite-lived acquired client relationships | 36.9 |
Tangible assets | 2.0 |
Deferred tax liability | (91.8 | )
Goodwill | 854.4 |
| $ | 1,362.3 |
Schedule of Changes in Equity Method Investments in Affiliates | The following table presents the change in Equity method investments in Affiliates:
| Total
Balance, as of December 31, 2016 | $ | 3,368.3 |
Equity method earnings | 303.3 |
Equity method intangible amortization | (71.7 | )
Distributions of earnings from equity method investments | (368.0 | )
Investments | 29.8 |
Foreign currency translation | 32.1 |
Other | (3.0 | )
Balance, as of September 30, 2017 | $ | 3,290.8 |

X
- Definition Schedule of Purchase Price Allocation of Equity Method Investments [Table Text Block] + References No definition available. + Details
Name: | amg_ScheduleofPurchasePriceAllocationofEquityMethodInvestmentsTableTextBlock
Namespace Prefix: | amg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of equity method investments including, but not limited to, name of each investee or group of investments, percentage ownership, difference between recorded amount of an investment and the value of the underlying equity in the net assets, and summarized financial information. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration