XML 79 R67.htm IDEA: XBRL DOCUMENT v3.21.1

Derivatives and Hedging Activity - Summary of Notional and Fair Values of Derivative Instruments (Detail) - USD ($)		Mar. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Notional Amount		$ 983,900,000	$ 598,600,000
Derivatives Assets		48,200,000	13,700,000
Derivative Liabilities		28,700,000	69,300,000
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional Amount		950,000,000.0	550,000,000.0
Interest Rate Contracts [Member] | Other current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives Assets		1,800,000
Interest Rate Contracts [Member] | Other noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives Assets		34,200,000
Interest Rate Contracts [Member] | Accrued compensation and other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities		25,800,000	54,500,000
Interest Rate Contracts [Member] | Other noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities			10,900,000
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	[1]	33,900,000	48,600,000
Foreign Exchange Contracts [Member] | Other current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives Assets	[1]	6,600,000	5,900,000
Foreign Exchange Contracts [Member] | Other noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives Assets		5,600,000	7,800,000
Foreign Exchange Contracts [Member] | Accrued compensation and other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[1]	400,000	600,000
Foreign Exchange Contracts [Member] | Other noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities		$ 2,500,000	$ 3,300,000
[1] Included within foreign exchange contracts at March 31, 2021 were $314.6 million of call options offset with $314.6 million of put options, and $15.3 million of buy forwards offset with $49.2 million of sell forwards.  Included within foreign exchange contracts at December 31, 2020 were $354.7 million of call options offset with $354.7 million of put options, and $9.0 million of buy forwards offset with $57.6 million of sell forwards.

X

- Definition

Nominal or face amount used to calculate payments on the derivative asset.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeAssetNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Nominal or face amount used to calculate payments on the derivative liability.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeLiabilityNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

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

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherCurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_BalanceSheetLocationAxis=ajg_AccruedCompensationAndOtherCurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: