SEGMENTS - Concentrations (Details) $ in Thousands	12 Months Ended
Dec. 31, 2025 USD ($) borrower	Dec. 31, 2024 USD ($) borrower	Dec. 31, 2023 USD ($)
Product concentration
Maximum borrower/key principal exposure benchmark (as a percent)	3.00%	3.00%
Servicing portfolio loans unpaid principal balance	$ 143,978,153	$ 135,287,012	$ 130,471,524
Debt financing volume	41,483,695	30,154,666	24,202,859
Fannie Mae DUS Program
Product concentration
Servicing portfolio loans unpaid principal balance	72,708,372	68,196,744	63,699,106
Debt financing volume	9,552,425	7,641,161	7,021,397
Freddie Mac
Product concentration
Servicing portfolio loans unpaid principal balance	42,595,441	39,185,091	39,330,545
Debt financing volume	8,248,816	5,227,550	4,568,935
Ginnie Mae-HUD
Product concentration
Servicing portfolio loans unpaid principal balance	11,563,020	10,847,265	10,460,884
Debt financing volume	915,524	588,529	678,889
Brokered
Product concentration
Debt financing volume	22,076,680	16,093,776	11,714,888
Principal Lending and Investing
Product concentration
Debt financing volume	690,250	603,650	218,750
Other
Product concentration
Servicing portfolio loans unpaid principal balance	$ 17,111,320	$ 17,057,912	$ 16,980,989
Revenue \| Customer Concentration \| Customer 1
Product concentration
Percent of revenue	36.90%	35.60%	34.80%
Revenue \| Risk-sharing Concentration
Product concentration
Number of borrower/key principals exceeding the risk-sharing benchmark \| borrower	0	0

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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