v3.26.1
Expense Example, No Redemption - Thornburg Investment Income Builder Fund - Class C
Aug. 20, 2026
USD ($)
Prospectus [Line Items]  
Expense Example, No Redemption, 1 Year $ 193
Expense Example, No Redemption, 3 Years 597
Expense Example, No Redemption, 5 Years 1,026
Expense Example, No Redemption, 10 Years $ 2,222