Dividends declared for outstanding common stock.

No definition available.

Name:	masi_DividendsDeclaredForOutstandingCommonStock
Namespace Prefix:	masi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity [Line Items]

+ References

No definition available.

+ Details

Name:	masi_EquityLineItems
Namespace Prefix:	masi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of right to be issued with each share of common stock.

+ References

No definition available.

+ Details

Name:	masi_NumberOfRightsToBeIssuedWithEachShareOfCommonStock
Namespace Prefix:	masi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Preferred stock voting rights per share.

+ References

No definition available.

+ Details

Name:	masi_PreferredStockVotingRightsPerShare
Namespace Prefix:	masi_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchase price per right.

+ References

No definition available.

+ Details

Name:	masi_PurchasePricePerRight
Namespace Prefix:	masi_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock Repurchase Program, Increase (Decrease) in Number of Shares Authorized to be Repurchased

+ References

No definition available.

+ Details

Name:	masi_StockRepurchaseProgramIncreaseDecreaseinNumberofSharesAuthorizedtobeRepurchased
Namespace Prefix:	masi_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.28)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29
-Article 5

+ Details

Name:	us-gaap_PreferredStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Period which shares may be purchased under a stock repurchase plan authorized by an entity's Board of Directors, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramPeriodInForce1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Total cost of shares repurchased divided by the total number of shares repurchased.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

+ Details

Name:	us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares that have been repurchased during the period and are being held in treasury.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Name:	us-gaap_TreasuryStockSharesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesAPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareRepurchaseProgramAxis=masi_A2013RepurchaseProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Equity - Additional Information (Detail)		1 Months Ended		12 Months Ended
Equity - Additional Information (Detail)	Nov. 08, 2007 shares $ / shares	Oct. 31, 2014 shares	Feb. 28, 2013 shares	Jan. 02, 2016 $ / shares shares	Jan. 03, 2015 $ / shares shares	Dec. 28, 2013 $ / shares shares
Equity [Line Items]
Dividends declared for outstanding common stock	One preferred stock purchase right
Preferred stock voting rights per share	$ 1.000
Par value of preferred stock under stockholder rights plan				$ 0.001	$ 0.001
Number of right to be issued with each share of common stock \| shares	1
Average cost per share				$ 37.36	$ 23.00	$ 19.79
Shares repurchased \| shares				4,148,000	4,455,000	1,000,000
Series A Preferred Stock
Equity [Line Items]
Par value of preferred stock under stockholder rights plan	$ 0.001
Purchase price per right	$ 136.00
Common Stock
Equity [Line Items]
Period of stock repurchase program			36 months
2013 Repurchase Program [Member] \| Common Stock
Equity [Line Items]
Number of common shares authorized to be repurchased under repurchase program \| shares		9,000,000	6,000,000.0
Stock Repurchase Program, Increase (Decrease) in Number of Shares Authorized to be Repurchased \| shares		3,000,000.0