Goodwill and Intangible Assets - Activity of Goodwill by Reportable Operating Segment (Detail) $ in Thousands		9 Months Ended
		Jul. 03, 2015 USD ($)
Goodwill [Roll Forward]
Balance, beginning	[1]	$ 240,626
Business acquisition		8,200
Foreign currency translation adjustments		(7,100)
Balance, ending		241,734
Oncology Systems
Goodwill [Roll Forward]
Balance, beginning		148,300
Business acquisition		0
Foreign currency translation adjustments		0
Balance, ending		148,300
Imaging Components
Goodwill [Roll Forward]
Balance, beginning		36,000
Business acquisition		8,200
Foreign currency translation adjustments		0
Balance, ending		44,200
Other
Goodwill [Roll Forward]
Balance, beginning		56,300
Business acquisition		0
Foreign currency translation adjustments		(7,100)
Balance, ending		$ 49,200

[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.