Summary of Activity with NCM Included in Company's Consolidated Financial Statements (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Company's beverage concessionaire advertising costs	$ 2,605	$ 11,478	$ 11,965
Screen Advertising Rental Revenue
Schedule Of Equity Method Investments [Line Items]
Revenues earned under ESA	$ 4,828