Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Mar. 28, 2014	Sep. 27, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Corporate debt security	$ 79.4	$ 62.7
Derivative assets	0.3
Option to purchase a company	1.4	1.4
Total assets measured at fair value	81.1	114.1
Derivative liabilities	(0.3)	(1.1)
Contingent consideration	(1.5)	(2.5)
Total liabilities measured at fair value	(1.8)	(3.6)
Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds		50.0
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Corporate debt security	0	0
Derivative assets	0
Option to purchase a company	0	0
Total assets measured at fair value		50.0
Derivative liabilities	0	0
Contingent consideration	0	0
Total liabilities measured at fair value	0	0
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds		50.0
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Corporate debt security	0	0
Derivative assets	0.3
Option to purchase a company	0	0
Total assets measured at fair value	0.3	0
Derivative liabilities	(0.3)	(1.1)
Contingent consideration	0	0
Total liabilities measured at fair value	(0.3)	(1.1)
Significant Other Observable Inputs (Level 2) | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds		0
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Corporate debt security	79.4	62.7
Derivative assets	0
Option to purchase a company	1.4	1.4
Total assets measured at fair value	80.8	64.1
Derivative liabilities	0	0
Contingent consideration	(1.5)	(2.5)
Total liabilities measured at fair value	(1.5)	(2.5)
Significant Unobservable Inputs (Level 3) | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds		$ 0