COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	37 Months Ended
	Jan. 31, 2022	Jun. 30, 2019	Apr. 27, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2016
Other Commitments [Line Items]
Fair value				$ 26,382	$ 283,599
Collateralized deposit				1,249,739	$ 998,902
Commitments to Extend Credit
Other Commitments [Line Items]
Commitment				110,400
SBA investment
Other Commitments [Line Items]
Commitment				14,300
504 Loan
Other Commitments [Line Items]
Commitment				81,700
Commercial & Industrial
Other Commitments [Line Items]
Commitment				14,400
BSP
Other Commitments [Line Items]
Investment						$ 5,400
Additional capital investment		$ 1,700
Net unrealized appreciation on controlled investments		(7,100)
Fair value		$ 0
Receivable And Inventory Facility | Line of Credit | Payment guarantee
Other Commitments [Line Items]
Guaranty liabilities				2,200
Receivable And Inventory Facility | Line of Credit | Payment guarantee | Asset Pledged as Collateral
Other Commitments [Line Items]
Collateralized deposit				750
NBL Capital One Facility | Line of Credit | Payment guarantee
Other Commitments [Line Items]
Guaranty liabilities				19,300
NBL Deutsche Bank Facility | Line of Credit | Payment guarantee
Other Commitments [Line Items]
Guaranty liabilities				7,100
NBL One Florida Bank Facility | Line of Credit | Payment guarantee
Other Commitments [Line Items]
Guaranty liabilities				13,700
Webster Facility | Line of Credit | Payment guarantee
Other Commitments [Line Items]
Guaranty liabilities				39,900
BSP
Other Commitments [Line Items]
Non-dischargeable judgement amount	$ 6,200
Newtek Business Credit Solutions | Receivable And Inventory Facility | Line of Credit
Other Commitments [Line Items]
Maximum borrowing capacity				5,000
Newtek Business Lending, LLC | NBL Capital One Facility | Line of Credit
Other Commitments [Line Items]
Maximum borrowing capacity				60,000
Accordion feature, increase limit				150,000
Newtek Business Lending, LLC | NBL Deutsche Bank Facility | Line of Credit
Other Commitments [Line Items]
Maximum borrowing capacity				50,000
Newtek Business Lending, LLC | NBL One Florida Bank Facility | Line of Credit
Other Commitments [Line Items]
Maximum borrowing capacity				20,000
Newtek Business Lending, LLC | NBL One Florida Bank Facility | Line of Credit | Subsequent Event
Other Commitments [Line Items]
Maximum borrowing capacity			$ 30,000
Newtek Merchant Solutions, LLC | Webster Facility | Line of Credit
Other Commitments [Line Items]
Maximum borrowing capacity				$ 54,900