FAIR VALUE - Assets - Assets and Liabilities Recorded at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	$ 3,940,860	$ 6,511,095
Derivative, Fair Value, Net	198,484	50,786
U.S. Treasury Notes	36,302	37,175
Interest Rate Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net		0
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	0	0
U.S. Treasury Notes	36,302	37,175
Fair Value, Inputs, Level 1 [Member] | Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	0	0
Fair Value, Inputs, Level 1 [Member] | Interest Rate Swaption [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	0	0
Fair Value, Inputs, Level 1 [Member] | TBA Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	0	0
Fair Value, Inputs, Level 1 [Member] | Interest Rate Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	3,940,860	6,511,095
U.S. Treasury Notes	0	0
Fair Value, Inputs, Level 2 [Member] | Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	104,137	26,431
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swaption [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	45,556	17,070
Fair Value, Inputs, Level 2 [Member] | TBA Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	1,362	(304)
Fair Value, Inputs, Level 2 [Member] | Interest Rate Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	3,837
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	0	0
U.S. Treasury Notes	0	0
Fair Value, Inputs, Level 3 [Member] | Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	0	0
Fair Value, Inputs, Level 3 [Member] | Interest Rate Swaption [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	0	0
Fair Value, Inputs, Level 3 [Member] | TBA Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	0	$ 0
Fair Value, Inputs, Level 3 [Member] | Interest Rate Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Fair Value, Net	$ 0