XML 63 R52.htm IDEA: XBRL DOCUMENT v3.19.1

Contracts with Customers - Summary of Expected Revenue Related to Performance Obligations (Detail) $ in Millions	Mar. 31, 2019 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	$ 480.1
2019 (remaining nine months) [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	332.7
2020 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	69.2
2021 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	37.7
2022 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	14.2
2023 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	6.7
Thereafter [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	19.6
Brokerage [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	309.5
Brokerage [Member] | 2019 (remaining nine months) [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	252.0
Brokerage [Member] | 2020 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	32.9
Brokerage [Member] | 2021 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	19.7
Brokerage [Member] | 2022 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	3.8
Brokerage [Member] | 2023 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	0.6
Brokerage [Member] | Thereafter [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	0.5
Risk Management [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	170.6
Risk Management [Member] | 2019 (remaining nine months) [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	80.7
Risk Management [Member] | 2020 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	36.3
Risk Management [Member] | 2021 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	18.0
Risk Management [Member] | 2022 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	10.4
Risk Management [Member] | 2023 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	6.1
Risk Management [Member] | Thereafter [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue related to performance obligations	$ 19.1

X

- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130556-203045

+ Details

Name:	us-gaap_RevenueRemainingPerformanceObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ajg_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateNonTypedAxis=ajg_JanuaryOne2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ajg_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateNonTypedAxis=ajg_JanuaryOne2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ajg_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateNonTypedAxis=ajg_JanuaryOne2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ajg_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateNonTypedAxis=ajg_JanuaryOne2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ajg_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateNonTypedAxis=ajg_JanuaryOne2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ajg_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateNonTypedAxis=ajg_ThereafterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ajg_BrokerageSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ajg_RiskManagementSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: