Summary Of Significant Accounting Policies (Accounting Changes To Consolidated Statements Of Income) (Details) - USD ($) $ / shares in Units, $ 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]
Revenue	$ 10,191			$ 70,386			$ 62,841	$ 207,886
Operating income (loss)	(17,375)			2,840			(46,610)	7,209
Income (loss) before income taxes	(19,842)			1,329			(53,265)	2,055
Income tax (expense) benefit	490			(528)			5,070	(1,101)
Net income (loss)	(19,352)	$ (22,888)	$ (5,956)	801	$ 2,294	$ (2,140)	(48,195)	954
Net income (loss) attributable to Reading International, Inc. common shareholders	$ (19,228)			$ 851			$ (47,806)	$ 1,057
Basic earnings (loss) per share	$ (0.88)			$ 0.04			$ (2.20)	$ 0.05
Diluted earnings (loss) per share	$ (0.88)			$ 0.04			$ (2.20)	$ 0.05
Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 7,339			$ 66,663			$ 54,866	$ 196,885
Tax Year 2019 [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue				70,386				207,886
Operating income (loss)				2,840				7,209
Income (loss) before income taxes				1,329				2,055
Income tax (expense) benefit				(528)				(1,101)
Net income (loss)				801				954
Net income (loss) attributable to Reading International, Inc. common shareholders				$ 851				$ 1,057
Basic earnings (loss) per share				$ 0.04				$ 0.05
Diluted earnings (loss) per share				$ 0.04				$ 0.05
Tax Year 2019 [Member] | Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue				$ 66,663				$ 196,885
Tax Year 2019 [Member] | As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue				70,456				208,102
Operating income (loss)				2,910				7,425
Income (loss) before income taxes				1,399				2,271
Income tax (expense) benefit				(547)				(1,159)
Net income (loss)				852				1,112
Net income (loss) attributable to Reading International, Inc. common shareholders				$ 902				$ 1,215
Basic earnings (loss) per share				$ 0.04				$ 0.05
Diluted earnings (loss) per share				$ 0.04				$ 0.05
Tax Year 2019 [Member] | As Reported [Member] | Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue				$ 66,733				$ 197,101
Tax Year 2019 [Member] | Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue				(70)				(216)
Operating income (loss)				(70)				(216)
Income (loss) before income taxes				(70)				(216)
Income tax (expense) benefit				19				58
Net income (loss)				(51)				(158)
Net income (loss) attributable to Reading International, Inc. common shareholders				(51)				(158)
Tax Year 2019 [Member] | Adjustments [Member] | Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue				$ (70)				$ (216)