Activity of Goodwill by Reportable Operating Segment (Detail) (USD $)	12 Months Ended
	Sep. 26, 2014	Sep. 27, 2013
Goodwill [Line Items]
Balance, beginning	$ 225,335,000	$ 222,200,000
Acquisition of business	19,100,000
Foreign currency translation adjustments	(3,800,000)	3,100,000
Balance, ending	240,626,000	225,335,000
Oncology Systems
Goodwill [Line Items]
Balance, beginning	132,000,000	132,000,000
Acquisition of business	16,300,000
Foreign currency translation adjustments	0	0
Balance, ending	148,300,000	132,000,000
Imaging Components
Goodwill [Line Items]
Balance, beginning	33,200,000	33,200,000
Acquisition of business	2,800,000
Foreign currency translation adjustments	0	0
Balance, ending	36,000,000	33,200,000
Other
Goodwill [Line Items]
Balance, beginning	60,100,000	57,000,000
Foreign currency translation adjustments	(3,800,000)	3,100,000
Balance, ending	$ 56,300,000	$ 60,100,000