Business Segments and Geographic Information - Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 26, 2016	Mar. 28, 2015	Mar. 26, 2016	Mar. 28, 2015	Sep. 26, 2015
Segment Reporting Information [Line Items]
Total revenues	$ 693.3	$ 655.5	$ 1,388.4	$ 1,308.3
Operating income (loss)	136.1	109.8	262.1	213.3
Depreciation and amortization	114.0	126.6	229.9	248.6
Capital expenditures	22.0	18.7	41.7	39.7
Identifiable assets	7,286.3		7,286.3		$ 7,670.1
Diagnostics
Segment Reporting Information [Line Items]
Total revenues	304.4	296.7	615.1	600.8
Operating income (loss)	34.3	27.1	65.8	55.3
Depreciation and amortization	83.8	91.9	167.4	180.5
Capital expenditures	13.0	11.4	24.9	26.2
Identifiable assets	3,912.0		3,912.0		4,055.8
Breast Health
Segment Reporting Information [Line Items]
Total revenues	275.8	255.5	537.9	497.5
Operating income (loss)	88.4	75.4	160.0	135.9
Depreciation and amortization	5.1	8.3	12.4	15.9
Capital expenditures	3.4	3.0	5.4	5.5
Identifiable assets	811.8		811.8		815.4
GYN Surgical
Segment Reporting Information [Line Items]
Total revenues	90.9	79.1	189.7	163.5
Operating income (loss)	11.5	4.5	32.3	17.7
Depreciation and amortization	24.8	26.0	49.5	51.5
Capital expenditures	3.4	2.4	6.8	4.4
Identifiable assets	1,612.2		1,612.2		1,658.1
Skeletal Health
Segment Reporting Information [Line Items]
Total revenues	22.2	24.2	45.7	46.5
Operating income (loss)	1.9	2.8	4.0	4.4
Depreciation and amortization	0.3	0.4	0.6	0.7
Capital expenditures	0.1	0.1	0.2	0.2
Identifiable assets	29.9		29.9		25.3
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	2.1	$ 1.8	4.4	$ 3.4
Identifiable assets	$ 920.4		$ 920.4		$ 1,115.5

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.18)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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