Fair Value Measurements - Valuation Techniques, Significant Unobservable Inputs, Quantitative Information Non-recurring Basis (Detail) - Discount factor applied to real estate collateral-based loans to reflect realizable value - Fair Value, Measurements, Nonrecurring - LEVEL 3 $ in Millions	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
INPUT VALUES	0.168	0.153
Lower Limit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
INPUT VALUES	0.150	0.150
Upper Limit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
INPUT VALUES	0.200	0.200
Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
FAIR VALUE	$ 24.6	$ 8.0