Debt (Narrative) (Detail) € in Millions, $ in Millions			1 Months Ended	3 Months Ended	9 Months Ended
	Jul. 02, 2018 USD ($)	Feb. 02, 2018 USD ($)	May 31, 2018	Sep. 28, 2018 USD ($) loan	Sep. 28, 2018 USD ($) loan	Sep. 28, 2018 EUR (€) loan	Jun. 29, 2018 USD ($)	May 15, 2018 USD ($)	Dec. 29, 2017 USD ($)	Nov. 24, 2014 USD ($)
Debt Instrument [Line Items]
Debt, Notes, Credit Facilities				$ 2,012.7	$ 2,012.7				$ 913.9
Uncommitted Facilities, floating rate
Debt Instrument [Line Items]
Debt, Notes, Credit Facilities				225.8	225.8				128.0
Senior Notes | 2023 Senior Notes, 4.15%, due June 2023
Debt Instrument [Line Items]
Debt Instrument, Principal				300.0	$ 300.0		$ 300.0		0.0
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate							4.15%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed					99.964%
Debt Issuance Costs, Gross				0.9	$ 0.9
Debt, Notes, Credit Facilities				300.0	300.0				0.0
Senior Notes | 2028 Senior Notes, 4.9%, due June 2028
Debt Instrument [Line Items]
Debt Instrument, Principal				600.0	$ 600.0		$ 600.0		0.0
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate							4.90%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed					99.867%
Debt Issuance Costs, Gross				1.8	$ 1.8
Debt, Notes, Credit Facilities				600.0	600.0				0.0
Senior Notes | 2024 Senior Notes, 4.75%, due December 2024
Debt Instrument [Line Items]
Debt Instrument, Principal				$ 400.0	$ 400.0				400.0	$ 400.0
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate				4.75%	4.75%	4.75%				4.75%
Debt Issuance Costs, Gross				$ 3.0	$ 3.0
Debt, Notes, Credit Facilities				400.0	400.0				400.0
Revolving Credit Facility | 2014 Credit Facility, floating rate, retired
Debt Instrument [Line Items]
Debt, Notes, Credit Facilities				$ 0.0	0.0				389.0
Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Covenant Ratio - Minimum Interest Coverage				3.50
Revolving Credit Facility | Revolving Credit Facility, due May 2023
Debt Instrument [Line Items]
Debt, Notes, Credit Facilities				$ 0.0	0.0				0.0
Promissory Notes And Other Debt
Debt Instrument [Line Items]
Promissory Notes and Other Debt, Current and Noncurrent				1.1	1.1				1.2
Promissory Notes And Other Notes, Noncurrent									0.8
Term Loan [Member] | 2018 Credit Facility
Debt Instrument [Line Items]
Debt, Notes, Credit Facilities				500.0	500.0
Revolving Credit Facility | Uncommitted Facilities, floating rate
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity				$ 75.0	$ 75.0
Number Of Revolving Loan Facilities | loan				2	2	2
Short-term Debt				$ 225.8	$ 225.8				$ 128.0
Short-term Debt, Weighted Average Interest Rate, at Point in Time				1.80%	1.80%	1.80%			2.24%
Revolving Credit Facility | Euro Uncommitted Facilities Three [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity | €						€ 100.0
Revolving Credit Facility | Uncommitted Facility Two [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity				$ 75.0	$ 75.0
2018 Credit Facility Maximum Leverage Ratio Permitted At End Of Third Quarter Fiscal 2018 [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Covenant Ratio - Maximum Leverage				3.50	3.50	3.50
2018 Credit Facility Maximum Leverage Ratio Permitted At End Of Three Fiscal Quarters Immediately Following Third Quarter Fiscal 2018 [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Covenant Ratio - Maximum Leverage				4.25	4.25	4.25
2018 Credit Facility Maximum Leverage Ratio Permitted At End Of Next Two Fiscal Quarters Immediately Following Third Quarter Fiscal 2018 [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Covenant Ratio - Maximum Leverage				3.75	3.75	3.75
2018 Credit Facility Leverage Ratio Permitted End Fiscal Quarter Material Acquisition Occurred And Each of Three Immediately Following Fiscal Quarters [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Covenant Ratio - Maximum Leverage				3.75	3.75	3.75
eBuilder [Member]
Debt Instrument [Line Items]
Purchase Consideration		$ 485.2			$ 485.2
Waterfall Holdings [Member]
Debt Instrument [Line Items]
Purchase Consideration	$ 1,211.2				1,211.2
Waterfall Holdings [Member] | Unsecured Bridge Term Loan [Member] | Bridge Loan
Debt Instrument [Line Items]
Line of Credit Facility, Periodic Payment, Interest					5.8
Material Acquisition [Member] | 2018 Credit Facility Leverage Ratio Permitted End Fiscal Quarter Material Acquisition Occurred And Each of Three Immediately Following Fiscal Quarters [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Purchase Consideration				$ 100.0
JPMorgan Chase Bank, N.A. [Member] | Unsecured Debt [Member] | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Issuance Costs, Gross				$ 4.9	$ 4.9
Line of Credit Facility, Current Borrowing Capacity								$ 1,750.0
JPMorgan Chase Bank, N.A. [Member] | Revolving Credit Facility | Unsecured Debt [Member] | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Term			5 years
Line of Credit Facility, Current Borrowing Capacity								1,250.0
JPMorgan Chase Bank, N.A. [Member] | Delayed Draw Term Loan [Member] | Unsecured Debt [Member] | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Term			3 years
Line of Credit Facility, Current Borrowing Capacity								500.0
JPMorgan Chase Bank, N.A. [Member] | Additional Loan Facility [Member] | Unsecured Debt [Member] | 2018 Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity								$ 500.0
Federal Funds Effective Swap Rate [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				0.50%
Credit facility, Variable Rate Basis Plus Percentage				1.00%
Reserve Adjusted One Month LIBOR [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				1 month
Reserve Adjusted One Month LIBOR [Member] | Revolving Credit Facility | Minimum | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				0.00%
Reserve Adjusted One Month LIBOR [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				0.875%
Adjustment LIBOR Rate One, Two, Three Or Six Month Interest Periods [Member] | Revolving Credit Facility | Minimum | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.00%
Adjustment LIBOR Rate One, Two, Three Or Six Month Interest Periods [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.875%
Adjusted LIBOR Rate One Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				1 month
Adjusted LIBOR Rate Two Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				2 months
Adjusted LIBOR Rate Three Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				3 months
Adjusted LIBOR Rate Six Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				6 months
Adjusted EURIBOR Rate, One, Two, Three Or Six Months Interest Periods [Member] | Revolving Credit Facility | Minimum | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.00%
Adjusted EURIBOR Rate, One, Two, Three Or Six Months Interest Periods [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.875%
Adjusted EURIBOR Rate One Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				1 month
Adjusted EURIBOR Rate Two Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				2 months
Adjusted EURIBOR Rate Three Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				3 months
Adjusted EURIBOR Rate Six Month Interest Period [Member] | Revolving Credit Facility | 2018 Credit Facility
Debt Instrument [Line Items]
Maturity Period, Variable Rate				6 months
EURIBOR Rate | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Interest Payable Periods On Borrowings				3 months
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility | Maximum | 2018 Credit Facility
Debt Instrument [Line Items]
Interest Payable Periods On Borrowings				3 months