XML 45 R32.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Affiliate Equity (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2017
Affiliate Equity [Abstract] |
Summary of Affiliate Equity Compensation | The following is a summary of Affiliate equity expense:
| For the Three Months Ended March 31,
| 2016 |  | 2017
Controlling interest | $ | 2.1 |  |  | $ | 4.0 |
Non-controlling interests | 3.9 |  |  | 12.6 |
Total | $ | 6.0 |  |  | $ | 16.6 |
Summary of Affiliate Equity Unrecognized Compensation Expense [Table Text Block] | The following is a summary of unrecognized Affiliate equity expense:
| Controlling Interest |  | Remaining Life |  | Non-controlling Interests |  | Remaining Life
December 31, 2016 | $ | 31.3 |  |  | 4 years |  | $ | 70.7 |  |  | 5 years
March 31, 2017 | 33.3 |  |  | 4 years |  | 84.6 |  |  | 5 years
Schedule of Changes in the Company's Interest in its Affiliates on the Controlling Interest's Equity | While the Company presents the current redemption value of Affiliate equity within Redeemable non-controlling interests with changes in the current redemption value increasing or decreasing the controlling interest’s equity over time, the following table discloses the cumulative effect that ownership changes had on the controlling interest’s equity related only to Affiliate equity transactions that settled during the periods:
| For the Three Months Ended March 31,
| 2016 |  | 2017
Net income (controlling interest) | $ | 104.0 |  |  | $ | 122.5 |
Decrease in controlling interest paid-in capital from purchases and sales of Affiliate equity issuances | (0.9 | ) |  | (1.2 | )
Decrease in controlling interest paid-in capital related to Affiliate equity repurchases | (17.5 | ) |  | (52.6 | )
Net income attributable to controlling interest and transfers from Non-controlling interests | $ | 85.6 |  |  | $ | 68.7 |

X
- Definition Affiliate Equity [Abstract] + References No definition available. + Details
Name: | amg_AffiliateEquityAbstract
Namespace Prefix: | amg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents a schedule of net income (loss) attributable to the entity and net transfers to non-controlling interest. + References No definition available. + Details
Name: | amg_ScheduleOfNetIncomeLossAttributableToEntityAndNetTransfersWithNoncontrollingInterestTableTextBlock
Namespace Prefix: | amg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary of Affiliate Equity Compensation [Table Text Block] + References No definition available. + Details
Name: | amg_SummaryofAffiliateEquityCompensationTableTextBlock
Namespace Prefix: | amg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary of Affiliate Equity Unrecognized Compensation Expense [Table Text Block] + References No definition available. + Details
Name: | amg_SummaryofAffiliateEquityUnrecognizedCompensationExpenseTableTextBlock
Namespace Prefix: | amg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration