XML 74 R64.htm IDEA: XBRL DOCUMENT
v3.23.2

Deferred Compensation - Additional Information (Detail) - USD ($) shares in Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2023 | Mar. 31, 2023 | Jun. 30, 2022 | Mar. 31, 2022 | Jun. 30, 2023 | Jun. 30, 2022 | Dec. 31, 2022
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |  |  |  |  |
Deferred Equity Participation Plan, distributions to key executives, age |  |  |  |  | age 62 (or the one-year anniversary of the date of the grant for participants over the age of 61 as of the grant date) or upon or after their actual retirement if later. |  |
Deferred Equity Participation Sub-plans, distributions requisite service description |  |  |  |  | we annually make awards under sub-plans of the DEPP for certain production staff, which generally provide for vesting and/or distributions no sooner than five years from the date of awards, although certain awards vest and/or distribute after the earlier of fifteen years or the participant reaching age 65. |  |
Deferred Equity Participation Sub-plans, distributions to key executives, age |  |  |  |  | age 65 |  |
Deferred Equity Participation Plan (DEPP) [Member] |  |  |  |  |  |  |
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |  |  |  |  |
Awards approved by committee, value |  | $ 25,100,000 |  | $ 26,300,000 |  |  |
Charge to compensation expenses related to awards | $ 5,900,000 |  | $ 5,000,000 |  | $ 9,900,000 | $ 8,500,000 |
Unearned deferred compensation, value |  |  |  |  | $ 97,800,000 |  | $ 77,700,000
Unearned deferred compensation, shares |  |  |  |  | 2.6 |  | 2.5
Total intrinsic value of unvested equity based awards |  |  |  |  | $ 566,900,000 |  | $ 478,700,000
Cash and equity awards with aggregate fair value vested and distributed to participants |  |  |  |  | 9,400,000 | 2,300,000 |
Deferred Equity Participation Plan Sub Plans [Member] |  |  |  |  |  |  |
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |  |  |  |  |
Awards approved by committee, value |  | 3,000,000 |  | 1,900,000 |  |  |
Charge to compensation expenses related to awards | 800,000 |  | 600,000 |  | 1,400,000 | 1,100,000 |
Distributions from the sub-plans |  |  |  |  | 6,400,000 | 0 |
Deferred Cash Participation Plan (DCPP) [Member] |  |  |  |  |  |  |
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |  |  |  |  |
Awards approved by committee, value |  | $ 9,800,000 |  | $ 8,300,000 |  |  |
Charge to compensation expenses related to awards | $ 4,200,000 |  | $ 3,300,000 |  | 8,000,000 | 6,000,000 |
Cash and equity awards with aggregate fair value vested and distributed to participants |  |  |  |  | $ 19,500,000 | $ 16,900,000 |

X
- Definition Cash and equity award with aggregate fair value vested and distributed to participants. + References No definition available. + Details
Name: | ajg_CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Compensation approved by committee, value + References No definition available. + Details
Name: | ajg_CompensationApprovedByCommitteeValue
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Deferred Equity Participation Plan, Distributions to Key Executives, Age + References No definition available. + Details
Name: | ajg_DeferredEquityParticipationPlanDistributionsToKeyExecutivesAge
Namespace Prefix: | ajg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Deferred equity participation sub plan distributions requisite service description. + References No definition available. + Details
Name: | ajg_DeferredEquityParticipationSubPlanDistributionsRequisiteServiceDescription
Namespace Prefix: | ajg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Deferred equity participation sub plan distributions to key executives age. + References No definition available. + Details
Name: | ajg_DeferredEquityParticipationSubPlanDistributionsToKeyExecutivesAge
Namespace Prefix: | ajg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Investments And Employee Deferred Compensation Plan [Line Items] + References No definition available. + Details
Name: | ajg_InvestmentsAndEmployeeDeferredCompensationPlanLineItems
Namespace Prefix: | ajg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Proceeds From Sub Plan + References No definition available. + Details
Name: | ajg_ProceedsFromSubPlan
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Unearned Deferred Compensation, Shares + References No definition available. + Details
Name: | ajg_UnearnedDeferredCompensationShare
Namespace Prefix: | ajg_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unearned Deferred Compensation, Value + References No definition available. + Details
Name: | ajg_UnearnedDeferredCompensationValue
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479830/718-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

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

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