Liability for Losses under Representations and Warranties - Summary of Company's Liability for Losses under Representations and Warranties (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Mortgage Banking [Abstract]
Balance, beginning of period	$ 13,183	$ 37,069	$ 26,143	$ 39,471
Provision for losses:
Pursuant to loan sales	459	448	917	2,126
Reduction in liability due to change in estimate	(5,180)	(4,365)	(18,598)	(7,920)
Losses incurred	(147)	0	(147)	(525)
Balance, end of period	8,315	33,152	8,315	33,152
UPB of loans subject to representations and warranties at end of period	$ 223,245,804	$ 228,679,429	$ 223,245,804	$ 228,679,429