Segment Information (Schedule Of Revenue, Operating Income And Identifiable Assets By Segment) (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 02, 2021	Apr. 03, 2020
Segment Reporting Information [Line Items]
Revenue	$ 886.5	$ 792.3
Acquired deferred revenue adjustment	0.2	1.7
Segment revenue	886.7	794.0
Amortization of acquired capitalized commissions	(1.2)	(1.5)
Consolidated segment operating income	140.9	98.3
Depreciation expense	10.3	9.8
Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	234.6	174.9
Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	233.6	175.1
Depreciation expense	5.9	5.9
Buildings and Infrastructure
Segment Reporting Information [Line Items]
Revenue	343.0	296.8
Acquired deferred revenue adjustment	0.1	0.1
Segment revenue	343.1	296.9
Amortization of acquired capitalized commissions	(1.1)	(1.4)
Buildings and Infrastructure | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	97.4	62.1
Buildings and Infrastructure | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	96.4	60.8
Depreciation expense	1.8	2.1
Geospatial
Segment Reporting Information [Line Items]
Revenue	181.7	146.2
Acquired deferred revenue adjustment	0.0	0.0
Segment revenue	181.7	146.2
Amortization of acquired capitalized commissions	0.0	0.0
Geospatial | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	48.7	30.5
Geospatial | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	48.7	30.5
Depreciation expense	1.7	1.4
Resources and Utilities
Segment Reporting Information [Line Items]
Revenue	205.2	179.0
Acquired deferred revenue adjustment	0.0	1.3
Segment revenue	205.2	180.3
Amortization of acquired capitalized commissions	0.0	0.0
Resources and Utilities | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	80.1	65.6
Resources and Utilities | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	80.1	66.9
Depreciation expense	1.5	1.3
Transportation
Segment Reporting Information [Line Items]
Revenue	156.6	170.3
Acquired deferred revenue adjustment	0.1	0.3
Segment revenue	156.7	170.6
Amortization of acquired capitalized commissions	(0.1)	(0.1)
Transportation | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	8.4	16.7
Transportation | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	8.4	16.9
Depreciation expense	$ 0.9	$ 1.1