v3.26.1
Document and Entity Information - shares
 3 Months Ended
Mar. 31, 2026
May 14, 2026
Document and Entity Information    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
Document Transition Report false  
Entity File Number 001-42718  
Entity Registrant Name Jefferson Capital, Inc. / DE  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 33-1923926  
Entity Address, Address Line One 600 SOUTH HIGHWAY 169  
Entity Address, Adress Line Two SUITE 1575  
Entity Address, City or Town MINNEAPOLIS  
Entity Address State Or Province MN  
Entity Address, Postal Zip Code 55426  
City Area Code 320  
Local Phone Number 229-8505  
Title of 12(b) Security Common stock, $0.0001 par value per share  
Trading Symbol JCAP  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   55,418,467
Entity Central Index Key 0002046042  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Amendment Flag false