Summary Financial Information for National CineMedia (Detail) - NCM - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2018	Jun. 29, 2017	Jun. 28, 2018	Jun. 29, 2017	Dec. 28, 2017
Schedule Of Equity Method Investments [Line Items]
Gross revenues	$ 113,700	$ 97,100	$ 193,900	$ 169,000
Operating income	40,100	28,300	51,100	33,400
Net income	25,000	$ 15,400	22,000	$ 7,500
Current assets	142,800		142,800		$ 174,400
Noncurrent assets	758,800		758,800		758,300
Current liabilities	84,800		84,800		123,300
Noncurrent liabilities	943,500		943,500		925,400
Members deficit	$ (126,700)		$ (126,700)		$ (116,000)