DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Summary of Fair Value of Derivative Instruments and Location in Statement of Financial Condition (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Derivatives Fair Value [Line Items]
Other Assets	$ 494,178	$ 213,513
Accounts payable and other liabilities	176,763	180,614
Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivatives Fair Value [Line Items]
Asset Derivative	332	372
Liability Derivatives	812	149
Not Designated as Hedging Instrument, Economic Hedge [Member] | Sale of TBA GNMA MBS pools [Member]
Derivatives Fair Value [Line Items]
Other Assets	0	0
Accounts payable and other liabilities	803	138
Not Designated as Hedging Instrument, Economic Hedge [Member] | Loan Origination Commitments [Member]
Derivatives Fair Value [Line Items]
Other Assets	20	20
Accounts payable and other liabilities	0	0
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Lock Commitments [Member]
Derivatives Fair Value [Line Items]
Other Assets	303	341
Accounts payable and other liabilities	0	0
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Cap [Member] | Written
Derivatives Fair Value [Line Items]
Other Assets	0	0
Accounts payable and other liabilities	9	11
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Cap [Member] | Purchase
Derivatives Fair Value [Line Items]
Other Assets	9	11
Accounts payable and other liabilities	$ 0	$ 0