Summary Of Significant Accounting Policies (Accounting Changes To Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance	$ 105,585	$ 117,399	$ 139,616	$ 177,023	$ 179,335	$ 179,979	$ 139,616	$ 179,979
Net income (loss) attributable to Reading International, Inc. common shareholders	(19,352)	(22,888)	(5,956)	801	2,294	(2,140)	(48,195)	954
Balance	90,207	105,585	117,399	162,988	177,023	179,335	90,207	162,988
Reading International Inc. Stockholders' Equity [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance	101,593	113,231	135,349	172,800	175,068	175,642	135,349	175,642
Net income (loss) attributable to Reading International, Inc. common shareholders	(19,228)	(22,703)	(5,875)	851	2,331	(2,124)
Balance	$ 86,306	$ 101,593	$ 113,231	158,789	$ 172,800	175,068	$ 86,306	158,789
Tax Year 2019 [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance						179,979		179,979
Net income (loss) attributable to Reading International, Inc. common shareholders				801				954
Balance				162,988				162,988
Tax Year 2019 [Member] | As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance						180,547		180,547
Net income (loss) attributable to Reading International, Inc. common shareholders				852				1,112
Balance				163,714				163,714
Tax Year 2019 [Member] | Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance						$ (568)		(568)
Net income (loss) attributable to Reading International, Inc. common shareholders				(51)				(158)
Balance				$ (726)				$ (726)