Fair Value Measurements - Investment Impairments and Credit Loss Reserves (Details) - USD ($) $ in Millions	3 Months Ended
Apr. 26, 2026	Jan. 25, 2026
Fair Value Disclosures [Abstract]
Credit loss reserve for held-to-maturity debt securities and available for sale debt securities	$ 3.8	$ 4.5
Decrease in credit loss reserve	$ 0.7

Debt Securities, Allowance For Credit Loss, Period Increase (Decrease)

No definition available.

Name:	smtc_DebtSecuritiesAllowanceForCreditLossPeriodIncreaseDecrease
Namespace Prefix:	smtc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration