LOANS - Fair Value and Unpaid Principal of Residential Mortgage Loan Portfolio (Details) - Residential Mortgage Loans - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Fair value	$ 18,332,573	$ 15,660,706
Unpaid principal balance	$ 19,364,991	$ 16,611,204

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

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