Receivables - Components of Current Finance and Contract Receivables (Additional Information) (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 30, 2017
Receivables [Abstract]
Unearned finance charges, finance receivables	$ 21.6	$ 21.0
Unearned finance charges, contract receivable	18.0	17.6
Unearned finance charges, finance receivables	17.1	16.7
Unearned finance charges, contract receivable	$ 26.5	$ 25.5