v3.26.1
Document and Entity Information - shares
 6 Months Ended
Mar. 31, 2026
May 08, 2026
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
Document Fiscal Year Focus 2026  
Document Transition Report false  
Entity File Number 000-56787  
Entity Registrant Name PENNANTPARK PRIVATE INCOME FUND  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 33-4777837  
Entity Address, Address Line One 1691 Michigan Avenue  
Entity Address, City or Town Miami Beach  
Entity Address, State or Province FL  
Entity Address, Postal Zip Code 33139  
City Area Code 786  
Local Phone Number 297-9500  
Title of 12(b) Security Common Shares, par value $0.001 per  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Common Stock, Shares Outstanding   4,670,568
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Shell Company false  
Entity Emerging Growth Company true  
Document Fiscal Period Focus Q2  
Entity Central Index Key 0002089126  
Current Fiscal Year End Date --09-30  
Amendment Flag false  
Entity Ex Transition Period true