Condensed Consolidated Statements of Cash Flows Supplemental Information - Write-downs (Parenthetical) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Film assets write downs on impairment loss			$ 10,200,000		$ 200,000
Film assets	$ 7,500,000		7,500,000
Film assets additional write downs			0
Other assets write down on impairment			1,200,000
Write-down of content-related assets			1,000,000.0
Theater system components written off in Costs and expenses			1,100,000		100,000
Theater system components written off in revenues					100,000
Write-downs for excess and obsolete inventory	$ 600,000	$ 0	$ 729,000	[1]	$ 0	[1]

[1] In the nine months ended September 30, 2020, the Company recorded write-downs of $0.7 million (2019 — $nil) related to excess inventory