Condensed Consolidated Statements of Cash Flows Supplemental Information - Write-downs (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019
Write-downs
Film assets	[1]			$ 10,211,000		$ 179,000
Other assets	[2]			1,151,000		0
Property, plant and equipment
Joint revenue sharing arrangements	[3]			1,050,000		748,000
Other property, plant and equipment				66,000		78,000
Inventories		$ 600,000	$ 0	729,000	[4]	0	[4]
Other intangible assets				132,000		22,000
Write-downs				$ 13,339,000		$ 1,027,000

[1] In the nine months ended September 30, 2020, the Company recorded impairment losses of $10.2 million (2019 — $0.2 million) principally to write-down the carrying value of certain documentary and alternative content film assets due to a decrease in projected box office totals and related revenues based on management’s regular quarterly recoverability assessments. To a much lesser extent, the impairment losses also relate to the write-down of DMR related film assets. As of September 30, 2020, following the recording of these write-downs, the Company’s film assets totaled $7.5 million, which principally consists of DMR and documentary content. There can be no assurances that there will not be additional write-downs to the carrying values of these assets as the Company continues to assess the ongoing impact of the COVID-19 pandemic (see Notes 1 and 2).

[2] In the nine months ended September 30, 2020, the Company recorded a $1.2 million (2019 — $nil) write-down of other assets, of which $1.0 million relates to the write-down of certain content-related assets which became impaired in the period.

[3] In the nine months ended September 30, 2020, the Company recorded charges of $1.1 million in Costs and Expenses Applicable to Technology Rentals principally related to the write-down of leased xenon-based digital systems which were taken out of service in connection with customer upgrades to laser-based digital systems. In the nine months ended September 30, 2019, the Company recorded a charge of $0.1 million in Costs and Expenses Applicable to Technology Rentals and  $0.1 million in Revenues -Technology Rentals related to the write-down of leased xenon-based digital systems which were taken out of service in connection with customer upgrades to laser-based digital systems.

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