v3.26.1
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
RMB Fund | RMB Fund, Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 12.49% 11.95% 21.19% (21.20%) 29.99% 15.93% 37.16% (2.84%) 22.49% 1.32%
RMB Mendon Financial Services Fund | RMB Mendon Financial Services Fund, Class A                    
Prospectus [Line Items]                    
Annual Return [Percent] 12.85% 17.06% 4.52% (19.00%) 56.44% (5.73%) 22.80% (17.02%) 11.99% 29.74%
RMB International Fund | RMB International Fund, Class I                    
Prospectus [Line Items]                    
Annual Return [Percent] 32.74% 0.02% 12.94% (16.94%) 9.53% 7.01% 19.20% (21.81%)    
RMB SMID Cap Fund | RMB SMID Cap Fund Class I                    
Prospectus [Line Items]                    
Annual Return [Percent] 2.55% 10.03% 20.06% (20.87%) 28.10% 24.39% 31.63% (4.89%) 13.66% 12.28%