Investment Securities - Gross Unrealized Losses and Fair Value, Aggregated by Investment Category (Detail) $ in Thousands	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	$ 135,579
Less Than 12 Months, Unrealized Losses	(647)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value	135,579
Unrealized Losses	(647)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	42,588
Less Than 12 Months, Unrealized Losses	(10)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value	42,588
Unrealized Losses	(10)
Agency-guaranteed mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	29,822
Less Than 12 Months, Unrealized Losses	(99)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value	29,822
Unrealized Losses	(99)
Corporate notes
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	50,620
Less Than 12 Months, Unrealized Losses	(164)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value	50,620
Unrealized Losses	(164)
Private label collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	12,549
Less Than 12 Months, Unrealized Losses	(374)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value	12,549
Unrealized Losses	$ (374)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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