XML 60 R41.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Convertible Securities (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2016
Debt Disclosure [Abstract] |
Schedule of Carrying Value of Convertible Securities | The carrying value and principal amount at maturity of the junior convertible securities were as follows:
|  | December 31, 2015 |  | December 31, 2016
|  | Carrying Value |  | Principal Amount at Maturity |  | Carrying Value |  | Principal Amount at Maturity
Junior convertible securities(1) |  | $ | 305.2 |  |  | $ | 430.8 |  |  | $ | 307.5 |  |  | $ | 430.8 |
__________________________
(1) | The carrying value is accreted to the principal amount at maturity over a remaining life of 21 years.

X
- Definition Tabular disclosure of the carrying amount and fair value of convertible securities. + References No definition available. + Details
Name: | amg_ScheduleOfConvertibleSecuritiesTableTextBlock
Namespace Prefix: | amg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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