Investment Portfolio Financing - Asset-Specific Financing Arrangements (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Outstanding principal amount	$ 3,917,842	$ 3,722,199
Long-term Debt	3,917,842
Unamortized deferred financing costs	8,800	10,100
Asset-specific financing arrangements
Debt Instrument [Line Items]
Outstanding principal amount	124,202	$ 0
Long-term Debt	124,202
Asset-specific financing arrangements | Financing
Debt Instrument [Line Items]
Debt, face value	289,802
Outstanding principal amount	124,202
Long-term Debt	$ 123,579
Weighted average credit spread (in percent)	3.60%
Weighted Average Term	2 years 7 months 6 days
Unamortized deferred financing costs	$ 600
Asset-specific financing arrangements | Collateral
Debt Instrument [Line Items]
Outstanding principal amount	$ 251,603
Weighted Average Term	1 year 4 months 24 days
Amortized cost of collateral	$ 247,107
Axos Bank | Asset-specific financing arrangements | Financing
Debt Instrument [Line Items]
Debt, face value	89,802
Outstanding principal amount	89,802
Long-term Debt	$ 89,351
Weighted average credit spread (in percent)	4.40%
Weighted Average Term	1 year 9 months 18 days
Axos Bank | Asset-specific financing arrangements | Collateral
Debt Instrument [Line Items]
Outstanding principal amount	$ 208,603
Weighted Average Term	2 months 12 days
Amortized cost of collateral	$ 204,519
BMO Facility | Asset-specific financing arrangements | Financing
Debt Instrument [Line Items]
Debt, face value	200,000
Outstanding principal amount	34,400
Long-term Debt	$ 34,228
Weighted average credit spread (in percent)	1.50%
Weighted Average Term	4 years 8 months 12 days
BMO Facility | Asset-specific financing arrangements | Collateral
Debt Instrument [Line Items]
Outstanding principal amount	$ 43,000
Weighted Average Term	4 years 8 months 12 days
Amortized cost of collateral	$ 42,588