Segment Information (Schedule Of Revenue, Operating Income And Identifiable Assets By Segment) (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017		Jun. 29, 2018	Jun. 30, 2017		Dec. 29, 2017
Segment Reporting Information [Line Items]
Revenue	$ 785.5	$ 659.9	[1],[2],[3]	$ 1,527.7	$ 1,270.5	[1],[2],[3]
Consolidated segment operating income	89.5	59.0	[2],[4]	153.7	113.7	[2],[4]
Depreciation expense				17.2	17.7	[5]
Accounts receivable	446.2			446.2			$ 427.7	[3],[6]
Inventories	282.4			282.4			264.6	[3],[6],[7]
Goodwill	2,682.1			2,682.1			2,287.1	[6]
Operating Segments [Member]
Segment Reporting Information [Line Items]
Consolidated segment operating income	182.4	138.0	[3],[4]	345.3	263.7	[3],[4]
Depreciation expense	5.1	5.0		10.0	10.1
Buildings and Infrastructure [Member]
Segment Reporting Information [Line Items]
Revenue	274.3	220.6	[1],[3]	499.0	407.1	[1],[3]
Accounts receivable	150.0			150.0			120.1	[3]
Inventories	64.6			64.6			62.1	[3]
Goodwill	1,119.7			1,119.7			706.8
Buildings and Infrastructure [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Consolidated segment operating income	67.4	47.8	[3]	110.9	79.5	[3]
Depreciation expense	1.4	1.5		2.8	3.3
Geospatial [Member]
Segment Reporting Information [Line Items]
Revenue	184.4	164.6	[1],[3]	358.9	314.2	[1],[3]
Accounts receivable	113.0			113.0			121.5	[3]
Inventories	127.2			127.2			110.3	[3]
Goodwill	406.1			406.1			415.3
Geospatial [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Consolidated segment operating income	41.6	29.8	[3]	78.9	57.7	[3]
Depreciation expense	1.5	1.5		2.9	2.8
Resources and Utilities [Member]
Segment Reporting Information [Line Items]
Revenue	145.0	111.6	[1],[3]	304.2	231.8	[1],[3]
Accounts receivable	75.3			75.3			78.5	[3]
Inventories	44.7			44.7			46.0	[3]
Goodwill	309.1			309.1			314.5
Resources and Utilities [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Consolidated segment operating income	42.3	35.0	[3]	94.0	77.6	[3]
Depreciation expense	1.0	0.6		2.0	1.2
Transportation [Member]
Segment Reporting Information [Line Items]
Revenue	181.8	163.1	[1],[3]	365.6	317.4	[1],[3]
Accounts receivable	107.9			107.9			107.6	[3]
Inventories	45.9			45.9			46.2	[3]
Goodwill	847.2			847.2			$ 850.5
Transportation [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Consolidated segment operating income	31.1	25.4	[3]	61.5	48.9	[3]
Depreciation expense	$ 1.2	$ 1.4		$ 2.3	$ 2.8

[1] Adjusted to reflect adoption of the new revenue recognition standard, Revenue from Contracts with Customers. For further information, see Note 2.

[2] See Note 2 for a summary of adjustments

[3] See Note 2 for a summary of adjustments

[4] See Note 2 for a summary of adjustments

[5] See Note 2 for a summary of adjustments

[6] See Note 2 for a summary of adjustments

[7] See Note 2 for a summary of adjustments