OFFSETTING ASSETS AND LIABILITIES - Offsetting of Assets (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Offsetting Assets [Line Items]
Derivative, Fair Value, Net	$ 0	$ 16,885,000
Gross Amount Of Assets Offset In The Balance Sheet		0
Net Amount Of Assets Presented In The Balance Sheet		16,885,000
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet		0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet		(14,431,000)
Net Amount Of Assets		2,454,000
Swap [Member]
Offsetting Assets [Line Items]
Gross Amount Of Assets Offset In The Balance Sheet		0
Net Amount Of Assets Presented In The Balance Sheet		16,762,000
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet		0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet		(14,308,000)
Net Amount Of Assets		2,454,000
TBA securities [Member]
Offsetting Assets [Line Items]
Gross Amount Of Assets Offset In The Balance Sheet		0
Net Amount Of Assets Presented In The Balance Sheet		0
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		0
Payer Swaption [Member]
Offsetting Assets [Line Items]
Gross Amount Of Assets Offset In The Balance Sheet		0
Net Amount Of Assets Presented In The Balance Sheet		123,000
Gross Amounts Of Financial Instruments Received Not Offset In Balance Sheet		0
Gross Amounts Of Cash Collateral Received Not Offset In Balance Sheet		(123,000)
Net Amount Of Assets		$ 0