Segment Information - Operating Results Information for Each Reportable Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 27, 2014	Jun. 28, 2013	Jun. 27, 2014	Jun. 28, 2013
Segment Reporting Information [Line Items]
Revenues	$ 747,685	$ 726,211	$ 2,237,693	$ 2,172,967
Operating Earnings (Loss)	142,504	154,732	412,042	447,926
Operating Segments | Oncology Systems
Segment Reporting Information [Line Items]
Revenues	578,200	561,300	1,722,700	1,667,400
Operating Earnings (Loss)	123,500	129,500	369,300	381,000
Operating Segments | Imaging Components
Segment Reporting Information [Line Items]
Revenues	161,800	158,200	492,000	474,600
Operating Earnings (Loss)	41,700	40,200	124,600	118,900
Operating Segments | Total reportable segments
Segment Reporting Information [Line Items]
Revenues	740,000	719,500	2,214,700	2,142,000
Operating Earnings (Loss)	165,200	169,700	493,900	499,900
Operating Segments | Other
Segment Reporting Information [Line Items]
Revenues	7,700	6,700	23,000	31,000
Operating Earnings (Loss)	(12,200)	(11,900)	(40,900)	(35,700)
Corporate
Segment Reporting Information [Line Items]
Operating Earnings (Loss)	$ (10,500)	$ (3,100)	$ (41,000)	$ (16,300)