Retirement Plans - Changes in Company's Assets and Related Obligations for its Pension Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Change in projected benefit obligations:
Projected benefit obligations at beginning of the year	$ 417.5	$ 392.8
Service cost pertaining to benefits earned during the year	7.2	6.5	$ 9.0
Interest cost on projected benefit obligations	17.7	19.1	18.5
Actuarial losses	30.5	31.0
Benefits paid to plan participants	(27.2)	(24.7)
Curtailment	(2.3)	0.0
Settlement	0.0	(7.2)
Projected benefit obligations at end of the year	443.4	417.5	392.8
Change in fair value of pension assets:
Fair value of pension assets at beginning of the year	271.9	280.8
Actual return on plan assets	41.0	19.1
Benefits paid to plan participants	(27.2)	(24.7)
Settlement	0.0	(7.2)
Fair value of pension assets at end of the year	299.6	271.9	$ 280.8
Funded status	(143.8)	(145.6)
Amounts recognized in the consolidated balance sheets:
Non-current assets	2.1	1.2
Current liabilities	(3.7)	(3.7)
Non-current liabilities	(142.2)	(143.1)
Net amount recognized	(143.8)	(145.6)
Funded status of pension plans and SERP (supplemental):
Funded status of qualified defined benefit plans and SERP	(143.8)	(145.6)
Nonqualified trust assets	60.7	56.6
Net funded status of pension plans and SERP (supplemental)	(89.8)	(95.5)
Pension [Member]
Change in fair value of pension assets:
Company contributions	11.3	1.5
SERP [Member]
Change in fair value of pension assets:
Company contributions	2.6	2.4
Funded status of pension plans and SERP (supplemental):
Nonqualified trust assets	$ 54.0	$ 50.1