Loans and Allowance for Credit Losses - Summary of Allowance for Credit Losses by Type (Detail) - USD ($) $ in Thousands	Sep. 30, 2023		Jun. 30, 2023	[2]	Dec. 31, 2022		Sep. 30, 2022	[1]	Jun. 30, 2022	[2]	Dec. 31, 2021	[2]
Financing Receivable Recorded Investment Past Due [Line Items]
Amount	$ 79,133	[1]	$ 74,971		$ 63,845	[2]	$ 61,535		$ 59,152		$ 50,166
Percentage of Allowance	100.00%				100.00%
Allowance as a Percent of Loan Category	3.59%				3.33%
Allowance as a Percent of Nonaccrual	383.25%				198.69%
Recreation [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Amount	$ 57,032				$ 41,966
Percentage of Allowance	72.00%				66.00%
Allowance as a Percent of Loan Category	4.24%				3.55%
Allowance as a Percent of Nonaccrual	276.21%				130.60%
Home Improvement [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Amount	$ 17,300				$ 11,340
Percentage of Allowance	22.00%				18.00%
Allowance as a Percent of Loan Category	2.31%				1.81%
Allowance as a Percent of Nonaccrual	83.79%				35.29%
Commercial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Amount	$ 3,114				$ 1,049
Percentage of Allowance	4.00%				1.00%
Allowance as a Percent of Loan Category	3.10%				1.13%
Allowance as a Percent of Nonaccrual	15.08%				3.26%
Medallion [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Amount	$ 1,687				$ 9,490
Percentage of Allowance	2.00%				15.00%
Allowance as a Percent of Loan Category	42.97%				69.93%
Allowance as a Percent of Nonaccrual	8.17%				29.53%

[1] As of September 30, 2023 and September 30, 2022, there were no allowance for credit losses and net charge-offs related to the strategic partnership loans.

[2] Represents allowance prior to the adoption of ASU 2016-13.