Receivables - Components of Current Finance and Contract Receivables (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 30, 2017
Receivables [Abstract]
Finance receivables, net of unearned finance charges of $21.6 million and $21.0 million, respectively	$ 530.5	$ 523.1
Contract receivables, net of unearned finance charges of $18.0 million and $17.6 million, respectively	93.3	98.1
Total	623.8	621.2
Allowances for doubtful accounts:
Finance receivables	(18.3)	(17.7)
Contract receivables	(1.3)	(1.3)
Total	(19.6)	(19.0)
Total current finance and contract receivables – net	604.2	602.2
Finance receivables – net	512.2	505.4
Contract receivables – net	92.0	96.8
Total current finance and contract receivables – net	604.2	602.2
Unearned finance charges, finance receivables	21.6	21.0
Unearned finance charges, contract receivable	$ 18.0	$ 17.6