v3.25.4
Annual Total Returns
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Thornburg Global Opportunities Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 40.70% 12.67% 15.91% (10.35%) 14.42% 22.32% 28.35% (20.92%) 21.64% 3.64%
Thornburg International Equity Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 33.83% 11.24% 15.77% (17.01%) 7.26% 22.36% 28.66% (20.05%) 24.98% (2.74%)
Thornburg Better World International Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 23.54% 6.53% 12.13% 20.39% (18.48%) 25.85% 23.72% (14.28%) 21.88% 6.76%
Thornburg International Growth Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 10.24% 2.04% 17.96% (26.33%) (4.46%) 33.94% 25.87% (17.01%) 34.33% (5.05%)
Thornburg Developing World Fund Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 27.31% 5.30% 6.13% (25.78%) (3.01%) 22.66% 29.03% (15.18%) 35.31% 2.55%
Thornburg Investment Income Builder Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 36.55% 13.13% 17.90% (8.27%) 20.02% (0.65%) 17.66% (4.62%) 14.78% 9.50%
Thornburg Summit Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 20.34% 11.15% 12.49%              
Thornburg Ultra Short Income Fund Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.61% 5.65% 5.57% 0.02% 0.12% 3.05% 3.74% 1.41% 1.31% 1.69%
Thornburg Limited Term U.S. Government Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 6.39% 2.40% 3.85% (7.97%) (1.83%) 3.77% 3.61% 0.83% 0.60% 0.90%
Thornburg Limited Term Income Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 6.80% 4.34% 6.27% (7.33%) (1.07%) 7.37% 5.37% 0.99% 2.27% 3.12%
Thornburg Core Plus Bond Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 7.43% 1.36%                
Thornburg Strategic Income Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 7.15% 4.45% 7.28% (6.62%) 2.43% 7.86% 7.55% 0.30% 6.01% 7.69%
Thornburg Short Duration Municipal Fund Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 3.53% 2.53% 3.46% (2.52%) (0.25%) 0.87% 1.91% 0.84% 0.89% 0.01%
Thornburg Limited Term Municipal Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.59% 1.30% 4.29% (5.11%) (0.19%) 2.96% 3.81% 0.88% 2.29% (0.69%)
Thornburg Intermediate Municipal Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.69% 1.84% 5.45% (6.41%) 0.99% 3.81% 5.64% 0.56% 3.61% (0.50%)
Thornburg Strategic Municipal Income Fund Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.02% 2.87% 5.89% (8.23%) 1.22% 3.79% 5.59% 0.74% 4.04% (0.38%)
Thornburg California Limited Term Municipal Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.66% 1.32% 4.17% (4.46%) (0.41%) 1.91% 3.20% 0.52% 2.05% (0.99%)
Thornburg New Mexico Intermediate Municipal Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.07% 0.64% 3.93% (6.27%) 0.10% 3.46% 4.49% 1.40% 2.03% (0.41%)
Thornburg New York Intermediate Municipal Fund - Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 3.84% 1.03% 4.75% (5.64%) 0.32% 2.99% 4.56% 0.16% 2.67% (0.51%)
Thornburg Global Opportunities Fund - Class R3                    
Prospectus [Line Items]                    
Annual Return [Percent] 40.43% 12.55% 15.69% (10.52%) 14.18% 22.05% 28.09% (21.07%) 21.37% 3.49%
Thornburg International Equity Fund - Class R3                    
Prospectus [Line Items]                    
Annual Return [Percent] 33.56% 11.05% 15.45% (17.13%) 7.10% 22.12% 28.39% (20.22%) 24.78% (2.88%)
Thornburg International Growth Fund - Class R3                    
Prospectus [Line Items]                    
Annual Return [Percent] 10.09% 1.93% 17.80% (26.36%) (4.69%) 33.64% 25.66% (17.18%) 34.22% (5.16%)
Thornburg Developing World Fund Class R5                    
Prospectus [Line Items]                    
Annual Return [Percent] 27.84% 5.75% 6.60% (25.51%) (2.65%) 23.08% 29.53% (14.88%) 35.84% 3.08%
Thornburg Investment Income Builder Fund - Class R3                    
Prospectus [Line Items]                    
Annual Return [Percent] 36.09% 12.68% 17.49% (8.62%) 19.59% (1.02%) 17.28% (5.01%) 14.49% 9.17%
Thornburg Limited Term U.S. Government Fund - Class R3                    
Prospectus [Line Items]                    
Annual Return [Percent] 6.47% 2.32% 3.90% (8.01%) (1.94%) 3.66% 3.52% 0.73% 0.56% 0.91%
Thornburg Limited Term Income Fund - Class R3                    
Prospectus [Line Items]                    
Annual Return [Percent] 6.56% 4.12% 6.04% (7.52%) (1.30%) 7.13% 5.15% 0.82% 2.15% 3.00%
Thornburg Strategic Income Fund - Class R3                    
Prospectus [Line Items]                    
Annual Return [Percent] 6.86% 4.06% 7.03% (6.81%) 2.11% 7.55% 7.23% 0.13% 5.95% 7.71%
Thornburg Emerging Markets Managed Account Fund - Class SMA                    
Prospectus [Line Items]                    
Annual Return [Percent] 12.19% (0.70%)                
Thornburg Municipal Managed Account Fund - Class SMA                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.96% 4.99%