Condensed Consolidated Statements of Cash Flows Supplemental Information - Write-downs (Details) - USD ($)		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Write-downs
Film assets	[1]	$ (44,000)	$ 2,302,000
Other assets	[2]	0	1,151,000
Property, plant and equipment
Equipment supporting joint revenue sharing arrangements	[3]	151,000	944,000
Other property, plant and equipment		3,000	6,000
Inventories	[4]	103,000	0
Write-downs		$ 213,000	$ 4,403,000

[1] In the first quarter of 2020, the Company recorded impairment losses of $2.3 million in Costs and Expenses Applicable to Image Enhancement and Maintenance Services principally to write-down the carrying value of certain documentary and alternative film content due to a decrease in projected box office totals and related revenues based on management’s regular quarterly recoverability assessments. Although no such impairment losses were recorded in the first quarter of 2021, 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 first quarter of 2020, the Company recorded a write-down of $1.0 million in Asset Impairments related to content-related assets which became impaired in the period. No such impairment loss was recorded in the first quarter of 2021.

[3] In the first quarter of 2021, the Company recorded charges of $0.2 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.

[4] In the three months ended March 31, 2021, the Company recorded write-downs of $0.1 million (2020 — $nil) in Costs and Expenses Applicable to Technology Sales related to excess inventory.