XML 63 R51.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Investment Information - Net investment income (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Net investment income: |  |  |  |  |
Gross investment income |  | $ 145,777 | $ 106,803 | $ 372,286 | $ 367,945
Investment expenses |  | (17,137) | (18,608) | (56,818) | (69,281)
Net investment income |  | 128,640 | 88,195 | 315,468 | 298,664
Fixed maturities |  |  |  |  |
Net investment income: |  |  |  |  |
Gross investment income |  | 123,568 | 75,964 | 310,963 | 255,215
Term loans |  |  |  |  |
Net investment income: |  |  |  |  |
Gross investment income |  | 88 | 1,736 | 2,106 | 33,343
Equity securities |  |  |  |  |
Net investment income: |  |  |  |  |
Gross investment income |  | 4,261 | 9,867 | 16,620 | 24,101
Short-term investments |  |  |  |  |
Net investment income: |  |  |  |  |
Gross investment income |  | 9,304 | 1,858 | 15,999 | 3,603
Other |  |  |  |  |
Net investment income: |  |  |  |  |
Gross investment income | [1] | $ 8,556 | $ 17,378 | $ 26,598 | $ 51,683
[1] | Includes income distributions from investment funds and other items.

X
- Definition Amount before accretion (amortization) of purchase discount (premium) of interest income and dividend income on nonoperating securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(a),(b)) -URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227 + Details
Name: | us-gaap_InvestmentIncomeInterestAndDividend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of expenses related to the generation of investment income. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.9) -URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.2) -URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
Name: | us-gaap_InvestmentIncomeInvestmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(a),(b)) -URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227 + Details
Name: | us-gaap_InvestmentIncomeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_FixedMaturitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=acgl_TermLoanInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_ShortTermInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=acgl_OtherInvestmentIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |