Segment Information - Operating Results Information for Each Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2015	Jun. 27, 2014	Jul. 03, 2015	Jun. 27, 2014
Segment Reporting Information [Line Items]
Revenues	$ 784,011	$ 747,685	$ 2,281,271	$ 2,237,693
Operating Earnings (Loss)	144,244	142,504	419,730	412,042
Operating Segments | Oncology Systems
Segment Reporting Information [Line Items]
Revenues	558,700	578,200	1,711,400	1,722,700
Operating Earnings (Loss)	110,600	123,500	362,600	369,300
Operating Segments | Imaging Components
Segment Reporting Information [Line Items]
Revenues	134,700	161,800	456,200	492,000
Operating Earnings (Loss)	23,200	41,700	104,400	124,600
Operating Segments | Total reportable segments
Segment Reporting Information [Line Items]
Revenues	693,400	740,000	2,167,600	2,214,700
Operating Earnings (Loss)	133,800	165,200	467,000	493,900
Operating Segments | Other
Segment Reporting Information [Line Items]
Revenues	90,600	7,700	113,700	23,000
Operating Earnings (Loss)	9,800	(12,200)	(16,500)	(40,900)
Corporate
Segment Reporting Information [Line Items]
Operating Earnings (Loss)	$ 600	$ (10,500)	$ (30,800)	$ (41,000)