v3.26.1
Marketable Securities - Gross Unrealized Losses and Fair Value of Marketable Securities (Detail) - USD ($)
$ in Thousands
Jan. 31, 2026
Jan. 31, 2025
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Fair Value $ 250,462 $ 301,391
Less Than 12 Months, Unrealized Losses (532) (1,007)
12 Months or Greater, Fair Value 14,147 16,828
12 Months or Greater, Unrealized Losses (16) (32)
Total, Fair Value 264,609 318,219
Total, Unrealized Losses (548) (1,039)
Corporate Bonds    
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Fair Value 197,823 206,917
Less Than 12 Months, Unrealized Losses (458) (587)
12 Months or Greater, Fair Value 5,338 8,093
12 Months or Greater, Unrealized Losses (6) (27)
Total, Fair Value 203,161 215,010
Total, Unrealized Losses (464) (614)
US Treasury Securities    
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Fair Value 22,491 37,007
Less Than 12 Months, Unrealized Losses (22) (94)
12 Months or Greater, Fair Value 0 1,495
12 Months or Greater, Unrealized Losses 0 (1)
Total, Fair Value 22,491 38,502
Total, Unrealized Losses (22) (95)
Federal Government Agencies    
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Fair Value 13,499 49,234
Less Than 12 Months, Unrealized Losses (47) (298)
12 Months or Greater, Fair Value 8,809 5,738
12 Months or Greater, Unrealized Losses (10) (1)
Total, Fair Value 22,308 54,972
Total, Unrealized Losses (57) (299)
Municipal And Pre-Refunded Municipal Bonds    
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Fair Value 15,629 6,917
Less Than 12 Months, Unrealized Losses (4) (13)
12 Months or Greater, Fair Value 0 1,502
12 Months or Greater, Unrealized Losses 0 (3)
Total, Fair Value 15,629 8,419
Total, Unrealized Losses (4) (16)
Mutual Funds, Held in Rabbi Trust    
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Fair Value 1,020 1,316
Less Than 12 Months, Unrealized Losses (1) (15)
12 Months or Greater, Fair Value 0 0
12 Months or Greater, Unrealized Losses 0 0
Total, Fair Value 1,020 1,316
Total, Unrealized Losses $ (1) $ (15)