OFFSETTING ASSETS AND LIABILITIES - Offsetting of Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Offsetting Assets [Line Items]
Gross Amount Of Recognized Assets	$ 47,383	$ 20,999
Gross Amount Of Assets Offset In The Balance Sheet	0	0
Net Amount Of Assets Presented In The Balance Sheet	47,383	20,999
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet	0	0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet	(13,765)	(6,083)
Net Amount Of Assets	33,618	14,916
Payer Swaption [Member]
Offsetting Assets [Line Items]
Gross Amount Of Recognized Assets	28,051	17,433
Gross Amount Of Assets Offset In The Balance Sheet	0	0
Net Amount Of Assets Presented In The Balance Sheet	28,051	17,433
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet	0	0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet	(13,765)	(3,563)
Net Amount Of Assets	14,286	13,870
TBA Contracts [Member]
Offsetting Assets [Line Items]
Gross Amount Of Recognized Assets		3,559
Gross Amount Of Assets Offset In The Balance Sheet		0
Net Amount Of Assets Presented In The Balance Sheet		3,559
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet		0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet		(2,520)
Net Amount Of Assets		1,039
Swap [Member]
Offsetting Assets [Line Items]
Gross Amount Of Recognized Assets	16,972	7
Gross Amount Of Assets Offset In The Balance Sheet	0	0
Net Amount Of Assets Presented In The Balance Sheet	16,972	7
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet	0	0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet	0	0
Net Amount Of Assets	16,972	$ 7
Interest Rate Floor [Member]
Offsetting Assets [Line Items]
Gross Amount Of Recognized Assets	2,360
Gross Amount Of Assets Offset In The Balance Sheet	0
Net Amount Of Assets Presented In The Balance Sheet	2,360
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet	0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet	0
Net Amount Of Assets	$ 2,360