Summary Of Significant Accounting Policies (Accounting Changes To Consolidated Statements Of Income) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2020	[1]	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	[1]	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 15,021		$ 10,191	$ 3,422	$ 49,228	$ 68,880		$ 70,386	$ 76,009	$ 61,493	$ 77,862	$ 276,768	$ 308,931
Operating income (loss)											(61,313)	9,123	23,624
Income (loss) before income taxes											(70,824)	2,334	17,464
Income tax (expense) benefit											(4,967)	28,837	3,298
Net income (loss)	(17,663)		(19,352)	(22,887)	(5,955)	(27,458)		801	2,294	(2,140)	(65,857)	(26,503)	14,166
Net income (loss) attributable to Reading International, Inc. common shareholders	$ (17,395)		$ (19,228)	$ (22,702)	$ (5,875)	$ (27,487)		$ 851	$ 2,331	$ (2,124)	$ (65,200)	$ (26,429)	$ 14,034
Basic earnings (loss) per share	$ (0.80)		$ (0.88)	$ (1.04)	$ (0.27)	$ (0.99)		$ 0.04	$ 0.10	$ (0.09)	$ (3.00)	$ (1.17)	$ 0.61
Diluted earnings (loss) per share	$ (0.80)		$ (0.88)	$ (1.04)	$ (0.27)	$ (0.99)		$ 0.04	$ 0.10	$ (0.09)	$ (3.00)	$ (1.17)	$ 0.60
Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue											$ 67,014	$ 262,189	$ 293,723
As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 15,021		$ 10,191	$ 3,422	$ 49,228	$ 68,880		$ 70,456	$ 76,096	$ 61,551
Net income (loss)	(17,663)		(19,352)	(22,887)	(5,955)	(27,458)		852	2,357	(2,097)
Net income (loss) attributable to Reading International, Inc. common shareholders	$ (17,395)		$ (19,228)	$ (22,702)	$ (5,875)	$ (27,487)		$ 902	$ 2,394	$ (2,081)
Basic earnings (loss) per share	$ (0.80)		$ (0.88)	$ (1.04)	$ (0.27)	$ (0.99)		$ 0.04	$ 0.10	$ (0.09)
Diluted earnings (loss) per share	$ (0.80)		$ (0.88)	$ (1.04)	$ (0.27)	$ (0.99)		$ 0.04	$ 0.10	$ (0.09)
Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue								$ (70)	$ (87)	$ (58)
Net income (loss)								(51)	(63)	(43)
Net income (loss) attributable to Reading International, Inc. common shareholders								$ (51)	$ (63)	$ (43)
Tax Year 2018 [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue													308,931
Operating income (loss)													23,623
Income (loss) before income taxes													17,463
Income tax (expense) benefit													(3,298)
Net income (loss)													14,166
Net income (loss) attributable to Reading International, Inc. common shareholders													$ 14,034
Basic earnings (loss) per share													$ 0.61
Diluted earnings (loss) per share													$ 0.60
Tax Year 2018 [Member] | Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue													$ 293,723
Tax Year 2018 [Member] | As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue													309,385
Operating income (loss)													24,078
Income (loss) before income taxes													17,918
Income tax (expense) benefit													(3,420)
Net income (loss)													14,498
Net income (loss) attributable to Reading International, Inc. common shareholders													$ 14,366
Basic earnings (loss) per share													$ 0.62
Diluted earnings (loss) per share													$ 0.62
Tax Year 2018 [Member] | As Reported [Member] | Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue													$ 294,177
Tax Year 2018 [Member] | Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue													(455)
Operating income (loss)													(455)
Income (loss) before income taxes													(455)
Income tax (expense) benefit													122
Net income (loss)													(332)
Net income (loss) attributable to Reading International, Inc. common shareholders													$ (332)
Basic earnings (loss) per share													$ (0.01)
Diluted earnings (loss) per share													$ (0.02)
Tax Year 2018 [Member] | Adjustments [Member] | Cinema [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue													$ (455)
Tax Year 2019 [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)													14,166
Net income (loss) attributable to Reading International, Inc. common shareholders													14,034
Tax Year 2019 [Member] | As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)													14,498
Net income (loss) attributable to Reading International, Inc. common shareholders													14,366
Tax Year 2019 [Member] | Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)													(332)
Net income (loss) attributable to Reading International, Inc. common shareholders													$ (332)

[1] Since previously published financial statements have been corrected, there is no impact on the fourth quarter results for 2019 or for the full year of 2020 and so no data is displayed here.