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Contracts with Customers - Summary of Expected Revenue Related to Performance Obligations (Detail) $ in Millions | Sep. 30, 2019 USD ($)
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Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | $ 493.9
2019 (remaining three months) [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 243.9
2020 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 165.1
2021 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 41.3
2022 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 17.4
2023 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 8.7
Thereafter [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 17.5
Brokerage [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 327.2
Brokerage [Member] | 2019 (remaining three months) [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 193.3
Brokerage [Member] | 2020 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 111.4
Brokerage [Member] | 2021 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 17.0
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 | 0.9
Brokerage [Member] | Thereafter [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 0.8
Risk Management [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 166.7
Risk Management [Member] | 2019 (remaining three months) [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 50.6
Risk Management [Member] | 2020 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 53.7
Risk Management [Member] | 2021 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 24.3
Risk Management [Member] | 2022 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 13.6
Risk Management [Member] | 2023 [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 7.8
Risk Management [Member] | Thereafter [Member] |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Expected revenue related to performance obligations | $ 16.7

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