ALLOWANCE FOR RISK-SHARING OBLIGATIONS - Summary of Allowance for Risk-Sharing Obligations (Detail) $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) loan
Allowance for Risk-Sharing Contracts
Beginning balance	$ 32,410		$ 44,057	$ 48,475		$ 62,636	$ 44,057	$ 62,636	$ 62,636
Provision (benefit) for risk-sharing obligations	555	$ (700)	$ (11,000)	1,183	$ (4,800)	$ (9,400)	(11,092)	(12,978)
Write-offs	(2,008)						(2,008)
Ending balance	30,957	$ 32,410		49,658	$ 48,475		$ 30,957	49,658	$ 44,057
Number of defaulted loans | loan							0		2
Amount of specific reserves placed on defaulted at risk loans									$ 4,400
Settlement of risk sharing obligation with Fannie Mae	2,000
Weighted average remaining life of the at risk servicing portfolio							6 years 7 months 6 days		7 years 2 months 12 days
Fannie Mae DUS program
Allowance for Risk-Sharing Contracts
Maximum quantifiable contingent liability associated with guarantees	$ 11,800,000			$ 10,800,000			$ 11,800,000	$ 10,800,000