Defined Contribution Plan, Number Of Plans

No definition available.

Name:	masi_DefinedContributionPlanNumberOfPlans
Namespace Prefix:	masi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480794/715-70-50-1

+ Details

Name:	us-gaap_DefinedContributionPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PlanNameAxis=masi_MasimoRetirementSavingsPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=us-gaap_ForeignPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Employee Benefits (Details) $ in Millions	3 Months Ended		9 Months Ended
Employee Benefits (Details) $ in Millions	Sep. 27, 2025 USD ($) plan	Sep. 28, 2024 USD ($)	Sep. 27, 2025 USD ($) plan	Sep. 28, 2024 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, number of plans \| plan	1		1
Masimo Retirement Savings Plan
Defined Contribution Plan Disclosure [Line Items]
Percent of employees' gross pay			100.00%
Percent of match			3.00%
Company's contribution to employee retirement savings plan	$ 0.7	$ 0.9	$ 2.7	$ 3.0
Masimo Retirement Savings Plan \| Foreign Plan
Defined Contribution Plan Disclosure [Line Items]
Company's contribution to employee retirement savings plan	$ 0.6	$ 0.5	$ 1.7	$ 1.5