v3.25.2
Document and Entity Information
6 Months Ended
Jun. 30, 2025
shares
Cover [Abstract]  
Document Type 10-Q
Amendment Flag false
Document Period End Date Jun. 30, 2025
Document Fiscal Year Focus 2025
Document Fiscal Period Focus Q2
Entity Registrant Name REDWOOD MORTGAGE INVESTORS IX
Entity Central Index Key 0001448038
Current Fiscal Year End Date --12-31
Entity Filer Category Non-accelerated Filer
Entity Small Business true
Entity Common Stock, Shares Outstanding 0
Entity Emerging Growth Company false
Entity Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Shell Company false
Document Quarterly Report true
Document Transition Report false
Entity File Number 000-55601
Entity Incorporation, State or Country Code DE
Entity Tax Identification Number 26-3541068
Entity Address, Address Line One 155 Bovet Road
Entity Address, Address Line Two Suite 302
Entity Address, City or Town San Mateo
Entity Address, State or Province CA
Entity Address, Postal Zip Code 94402
City Area Code 650
Local Phone Number 365-5341