MORTGAGE SERVICING RIGHTS - Fair Value Disclosures (Detail) - MSRs $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($) class	Dec. 31, 2019 USD ($)
Servicing
Number of classes of MSRs | class	1
Fair value of the MSRs	$ 959.0	$ 910.5
Sensitivity Analysis of Fair Value, example 1, impact of percent adverse change in discount rate, percent	1.00%
Decrease in fair value as a result of 100 basis point increase in discount rate	$ 28.6
Sensitivity Analysis of Fair Value, example 2, impact of percent adverse change in discount rate, percent	2.00%
Decrease in fair value as a result of 200 basis point increase in discount rate	$ 55.5