XML 82 R71.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Share-Based Payments - Share-based Payments - Non-Employee Directors RSUs (Details) - Restricted Share Units - shares | 6 Months Ended
--- | ---
Jun. 30, 2018 | Jun. 30, 2017
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |  |
RSUs granted, number of shares (in shares) | 230,766 | 174,488.707095856
Non-Employee Directors |  |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |  |
RSUs granted, number of shares (in shares) | 29,025 | 22,230
Board of Directors Chairman |  |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |  |
RSUs granted, number of shares (in shares) | 12,900 | 8,892

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_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=ahl_NonEmployeeDirectorsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=us-gaap_BoardOfDirectorsChairmanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |