Income Taxes - Effective Tax Rate Reconciliation Before ASU Adoption (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2026	Jan. 31, 2025	Jan. 31, 2024
Income Tax Disclosure [Abstract]
US federal statutory tax rate	$ 508,680	$ 276,270	$ 174,785
State taxes	39,700	56,336	37,137
Foreign rate differential		141	2,943
Non-deductible compensation		15,757	10,639
Stock-based compensation	25,274	58,770	96,936
Permanent items		10,371	4,016
Foreign-derived intangible income deduction	(42,360)	(56,630)	(63,571)
Research and development credits	(34,347)	(49,813)	(39,226)
Tax uncertainties	16,065	7,478	2,674
Changes in valuation allowance	5,503	(7,765)	(14,109)
Deferred rate change		(3,993)	(6,803)
Other	3,905	(1,576)	(10,570)
Total provision for income taxes	$ 522,137	$ 305,346	$ 194,850
Effective tax rate	21.60%	23.20%	23.40%