v3.26.1
Income Taxes - Additional Information (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Effective Income Tax Rate Reconciliation [Line Items]      
Statutory income tax rate 31.50% 31.50% 31.50%
Net changes in total valuation allowance ¥ 8,417 ¥ (3,201) ¥ 1,759
Net changes in total valuation allowance recognized in earnings due to the utilization of net operating loss carryforwards (1,877) (3,380) (3,660)
Increase in valuation allowance 2,968 1,143 4,125
Decrease in valuation allowance 812 3,129 3,612
Net changes in valuation allowance 2,156 ¥ (1,986) ¥ 513
Net operating loss carryforwards ¥ 339,611    
Statutory income tax rate before the revision   31.00%  
Increase in provision of income taxes   ¥ 6,124  
Statutory income tax rate after the revision   31.90%  
Japan national tax [Member]      
Effective Income Tax Rate Reconciliation [Line Items]      
Statutory income tax rate 25.60%