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Commitments, Contingencies and Off-Balance Sheet Arrangements - Off-Balance Sheet Commitments (Detail) $ in Millions | 3 Months Ended
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Mar. 31, 2018 USD ($)
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |
Amount of Commitment Expiration by Period - 2018 | $ 0.9
Amount of Commitment Expiration by Period - 2019 | 0.2
Amount of Commitment Expiration by Period - 2020 | 0.2
Amount of Commitment Expiration by Period - 2021 | 0.2
Amount of Commitment Expiration by Period - 2022 | 0.2
Amount of Commitment Expiration by Period - Thereafter | 17.3
Total Amounts Committed | 19.0
Letters of Credit [Member] |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |
Amount of Commitment Expiration by Period - 2018 | 0.7
Amount of Commitment Expiration by Period - Thereafter | 16.5
Total Amounts Committed | 17.2
Financial Guarantees [Member] |
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items] |
Amount of Commitment Expiration by Period - 2018 | 0.2
Amount of Commitment Expiration by Period - 2019 | 0.2
Amount of Commitment Expiration by Period - 2020 | 0.2
Amount of Commitment Expiration by Period - 2021 | 0.2
Amount of Commitment Expiration by Period - 2022 | 0.2
Amount of Commitment Expiration by Period - Thereafter | 0.8
Total Amounts Committed | $ 1.8

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- Details
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