v3.26.3
Shareholder Report, Line Graph (Details) - USD ($)
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Aug. 31, 2016
Aug. 31, 2026
Aug. 31, 2017
Aug. 31, 2018
Aug. 31, 2019
Aug. 31, 2020
Aug. 31, 2021
Aug. 31, 2022
Aug. 31, 2023
Aug. 31, 2024
Aug. 31, 2025
Aug. 31, 2026
C000006510 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   C with CDSC (1% for 12 months)                    
Accumulated Value $ 10,000   $ 11,548 $ 14,639 $ 16,002 $ 19,559 $ 25,298 $ 18,453 $ 20,325 $ 23,790 $ 26,569 $ 25,968
C000006509 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   B with CDSC (declining over six years from 4% to 0%)                    
Accumulated Value 10,000   11,556 14,649 16,010 19,563 25,307 18,462 20,335 23,798 26,567 25,976
C000006504 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   A with initial sales charge (5.75%)                    
Accumulated Value 9,425   10,975 14,013 15,433 19,008 24,766 18,195 20,196 23,819 26,792 26,391
C000107819 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   C with CDSC (1% for 12 months)                    
Accumulated Value 10,000   11,599 13,784 13,459 15,844 20,889 14,573 16,317 18,370 19,313 20,432
C000107818 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   B with CDSC (declining over six years from 4% to 0%)                    
Accumulated Value 10,000   11,599 13,784 13,459 15,844 20,888 14,573 16,326 18,370 19,313 20,431
C000107817 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   A with initial sales charge (5.75%)                    
Accumulated Value 9,425   11,013 13,184 12,965 15,380 20,428 14,359 16,203 18,378 19,469 20,750
C000159993 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   A with initial sales charge (5.75%)                    
Accumulated Value 9,425   12,065 11,972 11,161 12,125 15,129 11,888 12,339 14,649 17,452 24,927
C000159994 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   B with CDSC (declining over six years from 4% to 0%)                    
Accumulated Value 10,000   12,718 12,523 11,582 12,494 15,464 12,065 12,436 14,650 17,307 24,545
C000159995 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   C with CDSC (1% for 12 months)                    
Accumulated Value 10,000   12,706 12,518 11,579 12,490 15,459 12,055 12,427 14,638 17,296 24,521
C000160013 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   C with CDSC (1% for 12 months)                    
Accumulated Value 10,000   12,014 12,103 11,327 12,015 15,473 12,702 14,317 17,353 20,801 27,377
C000160012 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   B with CDSC (declining over six years from 4% to 0%)                    
Accumulated Value 10,000   12,014 12,102 11,326 12,012 15,476 12,693 14,318 17,347 20,804 27,372
C000160011 [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   A with initial sales charge (5.75%)                    
Accumulated Value 9,425   11,419 11,586 10,930 11,678 15,161 12,548 14,254 17,401 21,025 27,873
Russell 3000 Index [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   Russell 3000® Index                    
Accumulated Value 10,000   11,606 13,956 14,139 17,171 22,845 19,810 22,734 28,677 33,220 39,898
MSCI All Country World Index net div [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   MSCI All Country World Index (net div)                    
Accumulated Value 10,000   11,711 13,048 13,011 15,161 19,504 16,406 18,694 23,076 26,721 32,693
MSCI Emerging Markets Index net div [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   MSCI Emerging Markets Index (net div)                    
Accumulated Value 10,000   12,453 12,368 11,829 13,542 16,403 12,826 12,987 14,944 17,455 24,305
MSCI All Country World ex US Index net div [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   MSCI All Country World (ex-US) Index (net div)                    
Accumulated Value 10,000   11,888 12,266 11,865 12,852 16,048 12,915 14,451 17,083 19,717 25,109
Russell Midcap Growth Index [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   Russell Midcap® Growth Index                    
Accumulated Value 10,000   11,452 14,322 15,176 18,751 25,346 18,581 20,997 25,000 31,606 31,238
MSCI All Country World Small Mid Cap Index net div [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   MSCI All Country World Small Mid Cap Index (net div)                    
Accumulated Value $ 10,000   $ 11,627 $ 13,063 $ 12,275 $ 13,325 $ 18,417 $ 14,978 $ 16,249 $ 18,994 $ 21,649 $ 25,914