Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 25, 2016
Allowance for Doubtful Accounts Receivable [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 2,325	$ 919	$ 867
Additions, Charge to Costs and Expenses	2,311	1,127	403
Additions, Other		1,162
Deductions From Reserves	(338)	(883)	(351)
Balance at End of Year	4,298	2,325	919
Valuation Allowances for Deferred Tax Assets [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	7,634	3,123	5,891
Additions, Charge to Costs and Expenses	9,036	1,005	698
Additions, Other		3,506
Deductions From Reserves	(94)		(3,466)
Balance at End of Year	$ 16,576	$ 7,634	$ 3,123