GUARANTY OBLIGATION AND ALLOWANCE FOR RISK-SHARING OBLIGATIONS - Summary of Allowance for Risk-Sharing Obligations (Detail) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) loan	Mar. 31, 2021	Dec. 31, 2020
Allowance for Risk-Sharing Contracts
Beginning balance	$ 53,244	$ 62,636		$ 64,580	$ 62,636	$ 75,313	$ 75,313
Provision (benefit) for risk-sharing obligations	(4,769)			(4,251)	(14,161)	(14,984)
Ending balance	48,475	$ 53,244	$ 62,636	60,329	$ 48,475	60,329	$ 62,636
Number of defaulted loans | loan					3		3
Amount of specific reserves placed on defaulted at risk loans	10,800		$ 10,300		$ 10,800		$ 10,300
Fannie Mae DUS program
Allowance for Risk-Sharing Contracts
Maximum quantifiable contingent liability associated with guarantees	$ 10,500,000			$ 9,500,000	$ 10,500,000	$ 9,500,000
Fannie Mae DUS Program
Allowance for Risk-Sharing Contracts
Period of time used to determine the historical loss rate		10 years
Charge off rate for forecasted period	0.022%	0.03%		0.03%	0.022%	0.03%		0.04%	0.06%
Charge off rate for the remaining period	0.012%		0.018%		0.012%		0.018%
At risk servicing portfolio	$ 51,200,000				$ 51,200,000
CECL reserve for at risk servicing portfolio	$ 37,700		$ 52,300		$ 37,700		$ 52,300
Weighted average remaining life of the at risk servicing portfolio			7 years 6 months		7 years 3 months 18 days