Business Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 01, 2012	Oct. 02, 2011	Jul. 03, 2011	Apr. 03, 2011	Jan. 02, 2011	Oct. 03, 2010	Jul. 04, 2010	Apr. 04, 2010	Jan. 01, 2012	Jan. 02, 2011	Jan. 03, 2010
Sales:
Sales	$ 474.5	$ 496.4	$ 502.9	$ 468.1	$ 421.5	$ 409.8	$ 408.0	$ 404.9	$ 1,941.9	$ 1,644.2	$ 1,652.1
Income before taxes
Segment operating profit and other segment income									260.9	207.3	198.7
Corporate expense									(33.7)	(28.8)	(27.3)
Interest and debt expense, net									(16.2)	(6.5)	(4.8)
Other income (expense), net									0.6	1.6	(0.2)
Income from continuing operations before income taxes									211.6	173.6	166.4
Depreciation and amortization
Depreciation and amortization of assets									64.2	45.2	42.5
Capital expenditures
Total capital expenditures									41.7	31.0	33.5
Identifiable assets
Total identifiable assets	1,826.1				1,557.8				1,826.1	1,557.8	1,421.5
Instrumentation [Member]
Sales:
Sales									616.6	573.2	538.4
Income before taxes
Segment operating profit and other segment income									122.8	113.9	95.5
Depreciation and amortization
Depreciation and amortization of assets									16.3	16.6	16.0
Capital expenditures
Total capital expenditures									8.9	6.4	16.1
Identifiable assets
Total identifiable assets	545.0				575.0				545.0	575.0	541.5
Digital Imaging [Member]
Sales:
Sales									349.9	122.5	127.3
Income before taxes
Segment operating profit and other segment income									16.1	5.2	11.8
Depreciation and amortization
Depreciation and amortization of assets									26.9	9.3	9.6
Capital expenditures
Total capital expenditures									13.8	11.3	5.7
Identifiable assets
Total identifiable assets	638.8				192.0				638.8	192.0	179.8
Aerospace and Defense Electronics [Member]
Sales:
Sales									670.8	614.7	579.2
Income before taxes
Segment operating profit and other segment income									93.9	57.8	60.1
Depreciation and amortization
Depreciation and amortization of assets									16.9	16.0	14.0
Capital expenditures
Total capital expenditures									13.1	9.7	8.4
Identifiable assets
Total identifiable assets	479.3				460.7				479.3	460.7	415.2
Engineered Systems [Member]
Sales:
Sales									304.6	333.8	407.2
Income before taxes
Segment operating profit and other segment income									28.1	30.4	31.3
Depreciation and amortization
Depreciation and amortization of assets									4.0	3.1	2.7
Capital expenditures
Total capital expenditures									5.9	3.6	3.3
Identifiable assets
Total identifiable assets	115.1				106.9				115.1	106.9	92.8
Corporate [Member]
Depreciation and amortization
Depreciation and amortization of assets									0.1	0.2	0.2
Identifiable assets
Total identifiable assets	47.9				148.1				47.9	148.1	102.1
Discontinued Operations [Member]
Identifiable assets
Total identifiable assets					$ 75.1					$ 75.1	$ 90.1