v3.26.1
Share-based compensation - Summary of Restricted Stock and Restricted Stock Unit, Activity (Detail) - Restricted Stock Units (RSUs) [Member] - ¥ / shares
 12 Months Ended
Jun. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Outstanding balance   31,265,818 29,194,817 35,995,906
Granted   5,121,904 17,812,098 15,177,322
Vested   (10,575,870) (9,466,806) (11,276,824)
Forfeited   (4,133,306) (6,274,291) (10,701,587)
Outstanding balance   21,678,546 31,265,818 29,194,817
Expected to vest as of December 31, 2020,shares   18,454,254 25,950,949 24,487,867
Weighted average grant-date   ¥ 40.07 ¥ 54.42 ¥ 59.72
Granted,Weighted average grant-date   59.37 31.01 39.31
Vested,Weighted average grant-date   48.59 55.93 55.66
Forfeited,Weighted average grant-date   43.59 60.27 51.52
Weighted average grant date fair value   ¥ 40.45 ¥ 40.07 ¥ 54.42
2025 Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Outstanding balance   0    
Granted 28,506,786 34,496,154    
Vested (9,502,262) (2,066)    
Forfeited   (280,232)    
Outstanding balance   34,213,856 0  
Expected to vest as of December 31, 2020,shares   32,993,621    
Weighted average grant-date   ¥ 0    
Granted,Weighted average grant-date   43.26    
Vested,Weighted average grant-date   62.18    
Forfeited,Weighted average grant-date   72.22    
Weighted average grant date fair value   ¥ 43.02 ¥ 0