v3.25.2
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2025
Aug. 07, 2025
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 BLACKROCK TCP CAPITAL CORP.  
Entity Central Index Key 0001370755  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   85,036,467
Entity Shell Company false  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity File Number 814-00899  
Entity Tax Identification Number 56-2594706  
Entity Address, Address Line One 2951 28th Street  
Entity Address, Address Line Two Suite 1000  
Entity Address, City or Town Santa Monica  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 90405  
City Area Code 310  
Local Phone Number 566-1000  
Document Quarterly Report true  
Document Transition Report false  
Entity Incorporation, State or Country Code DE  
Title of 12(b) Security Common Stock, par value $0.001 per share  
Trading Symbol TCPC  
Security Exchange Name NASDAQ