v3.26.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Estimated Useful Lives of Assets (Details)
Dec. 31, 2025
Furniture and fixtures  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 7 years
Office equipment  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 5 years
Computers and equipment  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 3 years
Leasehold improvements | Minimum  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 5 years
Leasehold improvements | Maximum  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 8 years
Internal-use software and website development costs | Minimum  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 1 year
Internal-use software and website development costs | Maximum  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 5 years
Prosper Funding LLC | Internal-use software and website development costs | Minimum  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 1 year
Prosper Funding LLC | Internal-use software and website development costs | Maximum  
Property, Plant and Equipment [Line Items]  
Property and equipment, estimated useful life 5 years