Goodwill and Intangible Assets - Activity of Goodwill by Reportable Operating Segment (Detail) (USD $)	6 Months Ended
	Apr. 03, 2015
Goodwill [Roll Forward]
Balance, beginning	$ 240,626,000	[1]
Foreign currency translation adjustments	(8,000,000)
Balance, ending	232,633,000
Oncology Systems
Goodwill [Roll Forward]
Balance, beginning	148,300,000
Foreign currency translation adjustments	0
Balance, ending	148,300,000
Imaging Components
Goodwill [Roll Forward]
Balance, beginning	36,000,000
Foreign currency translation adjustments	0
Balance, ending	36,000,000
Other
Goodwill [Roll Forward]
Balance, beginning	56,300,000
Foreign currency translation adjustments	(8,000,000)
Balance, ending	$ 48,300,000

[1] The condensed consolidated balance sheet as of September 26, 2014 was derived from audited financial statements as of that date, but does not include all disclosures required by accounting principles generally accepted in the United States of America.