Mortgage Loan Participation Purchase and Sale Agreement - Summary of Mortgage Loan Participation Purchase and Sale Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
At period end:
Mortgage loan participation purchase and sale agreements	$ 28,790		$ 28,790		$ 0
Mortgage Loan Participation Purchase and Sale Agreement [Member]
Mortgage Loan Participation Purchase And Sale Agreement [Line Items]
Average balance	$ 32,353	$ 22,043	$ 18,829	$ 20,991
Weighted average interest rate	6.59%	6.69%	6.66%	6.46%
Total interest expense	$ 568	$ 403	$ 1,033	$ 1,109
Maximum daily amount outstanding	78,068	$ 46,303	78,068	$ 90,565
At period end:
Amount outstanding	28,878		28,878
Unamortized debt issuance costs	(88)		(88)
Mortgage loan participation purchase and sale agreements	28,790		$ 28,790
Weighted average interest rate			6.10%
Loans acquired for sale pledged to secure	$ 30,178		$ 30,178