Summary of Revenues Disaggregated Based on Timing of Revenue Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2021		Jun. 30, 2020	Jun. 30, 2021		Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 294,652		$ 8,974	$ 409,013		$ 552,590
U.S. Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	269,261		8,155	366,350	[1]	435,598	[1]
International Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	25,391		819	42,663		116,992
Goods and Services Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total revenues	273,328		166	368,174		502,860
Goods and Services Transferred at a Point in Time | U.S. Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	249,427		89	329,961	[1]	401,531	[1]
Goods and Services Transferred at a Point in Time | International Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	23,901		77	38,213		101,329
Goods and Services Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenues	21,324	[2]	8,808	40,839	[2]	49,730
Goods and Services Transferred Over Time | U.S. Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	19,834	[2]	8,066	36,389	[1],[2]	34,067	[1]
Goods and Services Transferred Over Time | International Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,490	[2]	$ 742	$ 4,450	[2]	$ 15,663

[1] U.S. segment revenues include eliminations of intercompany transactions with the international operating segment.  See Note 17 for additional information on intercompany eliminations.

[2] Amount includes amortization of NCM screen advertising advances.  See Deferred Revenues below.