SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Detail) shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Jan. 03, 2020 USD ($)		Sep. 27, 2019 USD ($)	[2]	Jun. 28, 2019 USD ($)	[3]	Mar. 29, 2019 USD ($)	[4]	Dec. 28, 2018 USD ($)		Sep. 28, 2018 USD ($)	[6]	Jun. 29, 2018 USD ($)	[7]	Mar. 30, 2018 USD ($)	[8]	Jan. 03, 2020 USD ($) shares	Dec. 28, 2018 USD ($) shares	Dec. 29, 2017 USD ($) shares	Dec. 29, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Fiscal year term																	53 weeks	52 weeks	52 weeks
Cash and cash equivalent maturity period maximum																	3 months
Allowance for doubtful accounts	$ 30.4								$ 39.9								$ 30.4	$ 39.9
Provision for doubtful accounts																	10.1	8.5	$ 10.0
Inventories	1,354.7								1,440.4								1,354.7	1,440.4
Inventory valuation reserves	50.0								51.5								50.0	51.5
Property and equipment	174.9								163.3								174.9	163.3
Depreciation																	37.2	31.7	28.2
Capitalized costs for computer software, net	$ 60.8								64.7								60.8	64.7
Capitalized costs for computer software, amortization																	7.2	6.6	5.5
Interest costs capitalized																	0.9	0.1	0.3
Impairment of intangible assets																	0.0	0.0	5.7
Average amortization of intangible assets																	$ 33.6
Years of average amortization of intangible assets																	5 years
Rate of foreign currency denominated accounts not hedged																	100.00%
Number of products	600,000																600,000
Reserve for returns and credits provided to customers																	$ 36.7	35.0
Deferred revenue, current	$ 11.6								17.2								11.6	17.2
Recognition of deferred revenue																	14.9
Advertising and promotion costs																	15.6	15.8	10.6
Shipping and handling costs	1,791.8	[1]	$ 1,775.8		$ 1,812.6		$ 1,689.6		1,689.1	[5]	$ 1,754.9		$ 1,718.8		$ 1,579.4		$ 7,069.8	$ 6,742.2	$ 6,356.4
Percentage threshold for tax benefit recognized																	50.00%
Stock options and units | shares																	0.2	0.3	0.4
Operating leases	273.3								0.0								$ 273.3	$ 0.0		$ 244.1
Operating Lease, Liability	282.0																282.0			$ 249.6
Reclassification of tax effects																	7.7
Finance Lease, Right-of-Use Asset	8.4																8.4
Gross [Member]
Summary Of Significant Accounting Policies [Line Items]
Notional amount of foreign currency forward contracts	130.2								96.3								130.2	96.3
Net [Member]
Summary Of Significant Accounting Policies [Line Items]
Notional amount of foreign currency forward contracts	95.4								75.7								95.4	75.7
Equipment And Computer Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment	126.0								125.8								126.0	125.8
Building and Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment	39.5								36.5								39.5	36.5
Land [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment	$ 1.0								$ 1.0								$ 1.0	1.0
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of days between performance obligation satisfaction and payment																	30 days
Minimum [Member] | Equipment And Computer Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life																	2 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of days between performance obligation satisfaction and payment																	60 days
Maximum [Member] | Equipment And Computer Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life																	20 years
Maximum [Member] | Building and Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life																	40 years
Shipping and Handling [Member]
Summary Of Significant Accounting Policies [Line Items]
Shipping and handling costs																	$ 133.1	$ 139.7	$ 119.1

[1] In the fourth quarter of 2019, "Operating income" includes $8.6 million of intangible asset amortization and $12.8 million of merger costs. "Net income" includes a $45.9 million tax benefit related to the reversal of deferred income tax valuation allowances, partially offset by $0.8 million of tax expense related to prior year tax positions.

[2] In the third quarter of 2019, "Operating income" includes $8.8 million of intangible asset amortization.

[3] In the second quarter of 2019, "Operating income" includes $8.8 million of intangible asset amortization.

[4] In the first quarter of 2019, "Operating income" includes $8.8 million of intangible asset amortization and a reversal of acquisition and integration costs of $0.3 million.

[5] In the fourth quarter of 2018, "Operating income" includes $8.7 million of intangible asset amortization and $0.2 million of U.K. facility relocation costs. "Income before income taxes" includes a $4.6 million loss on extinguishment of debt.

[6] In the third quarter of 2018, "Operating income" includes $9.6 million of intangible asset amortization, a restructuring charge of $0.2 million, $0.3 million of acquisition and integration costs and $0.2 million of U.K. facility relocation costs.

[7] In the second quarter of 2018, "Operating income" includes $9.7 million of intangible asset amortization, a restructuring charge of $9.2 million, $2.3 million of acquisition and integration costs, $2.6 million of CEO retirement agreement expense and $0.4 million of U.K. facility relocation costs.

[8] In the first quarter of 2018, "Operating income" includes $9.3 million of intangible asset amortization, $0.3 million of acquisition and integration costs and $0.2 million of U.K. facility relocation costs.