Commitments, Contingencies and Off-Balance Sheet Arrangements - Off-Balance Sheet Commitments (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2022	$ 1.8
Amount of Commitment Expiration by Period - 2023	1.4
Amount of Commitment Expiration by Period - 2024	2.0
Amount of Commitment Expiration by Period - 2025	0.2
Amount of Commitment Expiration by Period - 2026	0.1
Amount of Commitment Expiration by Period - Thereafter	17.1
Total Amounts Committed	22.6
Funding Commitments [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2022	0.5
Total Amounts Committed	0.5
Financial Guarantees [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2022	1.3
Amount of Commitment Expiration by Period - 2023	1.4
Amount of Commitment Expiration by Period - 2024	2.0
Amount of Commitment Expiration by Period - 2025	0.2
Amount of Commitment Expiration by Period - 2026	0.1
Amount of Commitment Expiration by Period - Thereafter	0.1
Total Amounts Committed	5.1
Letters of Credit [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - Thereafter	17.0
Total Amounts Committed	$ 17.0