Assets and liabilities measured at fair value (Details) - USD ($) $ in Thousands	Oct. 31, 2025	Jan. 31, 2025
Liabilities:
Current portion of long-term obligations	$ 15,799	$ 519,463
Long-term obligations	5,119,464	$ 5,719,025
Reported amount | Current portion of long-term debt obligations
Liabilities:
Current portion of long-term obligations	15,799
Reported amount | Long-term obligations
Liabilities:
Long-term obligations	5,119,464
Reported amount | Accrued expenses and other current liabilities
Liabilities:
Deferred compensation	5,640
Reported amount | Noncurrent Other liabilities
Liabilities:
Deferred compensation	48,726
Fair value measurements on recurring basis | Balance at the end of the period
Liabilities:
Current and long-term obligations	5,114,152
Deferred compensation	54,366
Fair value measurements on recurring basis | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1)
Liabilities:
Current and long-term obligations	4,956,823
Deferred compensation	54,366
Fair value measurements on recurring basis | Significant Other Observable Inputs (Level 2)
Liabilities:
Current and long-term obligations	$ 157,329