XML 83 R67.htm IDEA: XBRL DOCUMENT
v3.21.2

Variable Interest Entities and Noncontrolling Interests - Variable interest entity (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 1 Months Ended | 6 Months Ended | 9 Months Ended
--- | --- | --- | --- | ---
Jul. 01, 2021 | Mar. 31, 2014 | Jun. 30, 2021 | Sep. 30, 2021 | Sep. 30, 2020
Variable Interest Entity [Line Items] |  |  |  |  |
Net cash provided by (used for) operating activities |  |  |  | $ 2,627,551 | $ 2,331,450
Net cash provided by (used for) investing activities |  |  |  | (1,453,284) | (2,608,418)
Net cash (used for) provided by financing activities |  |  |  | $ (881,879) | 566,090
Watford Holdings Ltd | Merger Agreement |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Business acquisition, share price (per share) | $ 35.00 |  |  |  |
Greysbridge |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Percentage ownership after merger transaction | 40.00% |  |  |  |
Greysbridge | Kelso And Company |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Noncontrolling interest, ownership percentage by noncontrolling owners | 30.00% |  |  |  |
Greysbridge | Warburg Pincus LLC |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Noncontrolling interest, ownership percentage by noncontrolling owners | 30.00% |  |  |  |
Variable Interest Entity, Primary Beneficiary | Watford Holdings Ltd |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Initial investment contribution amount |  | $ 100,000 |  |  |
Ownership percentage |  | 11.00% |  |  |
Net cash provided by (used for) operating activities |  |  | $ 47,000 |  | 133,600
Net cash provided by (used for) investing activities |  |  | 96,300 |  | 242,000
Net cash (used for) provided by financing activities |  |  | $ (2,000) |  | $ (279,700)

X
- Definition Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination. + References No definition available. + Details
Name: | us-gaap_BusinessAcquisitionSharePrice
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3521-108585 + Details
Name: | us-gaap_NetCashProvidedByUsedInFinancingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3521-108585 + Details
Name: | us-gaap_NetCashProvidedByUsedInInvestingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3536-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3521-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585 + Details
Name: | us-gaap_NetCashProvidedByUsedInOperatingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash outflow associated with the acquisition of a controlling interest in another entity or an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, joint venture or equity method investment). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of subsidiary's or equity investee's stock owned by parent company after stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 5A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=123419778&loc=SL6759159-111685 + Details
Name: | us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=acgl_WatfordHoldingsLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=acgl_MergerAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=acgl_GreysbridgeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=acgl_KelsoAndCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=acgl_WarburgPincusLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |