Borrowings and Subordinated Debentures - Schedule of Borrowings (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Outstanding Balance
Overnight advances	$ 250,000	$ 250,000
Outstanding advances	$ 100,000	$ 100,000
Weighted Average Rate
Overnight advances (percent)	5.11%	4.65%
Outstanding advances (percent)	4.11%	3.57%
FHLB of San Francisco
Outstanding Balance
Overnight advances	$ 250,000	$ 250,000
Advances due within 12 months	50,000	50,000
Advances due over 12 months through 24 months	25,000	37,500
Advances due over 24 months through 36 months	25,000	12,500
Outstanding advances	$ 350,000	$ 350,000
Weighted Average Rate
Overnight advances (percent)	5.11%	4.65%
Advances due within 12 months (percent)	0.37%	0.97%
Advances due over 12 months through 24 months (percent)	1.22%	0.40%
Advances due over 24 months through 36 months (percent)	4.44%	1.90%
Outstanding advances (percent)	4.11%	3.57%