Non-controlling Interests (Summary Of Changes In Controlling And Non-controlling Stockholders’ Equity) (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Balance			$ (40,407,000)				$ (40,407,000)
Balance	$ 117,199,000	$ 95,749,000	81,173,000	$ 105,585,000	$ 117,399,000	$ 139,616,000	81,173,000	$ 139,616,000
Net income (loss)	(10,200,000)	22,594,000	22,067,000	(19,352,000)	(22,888,000)	(5,956,000)	34,461,000	(48,195,000)
Other comprehensive income, net	(4,029,000)	(1,592,000)	(2,545,000)	3,590,000	10,716,000	(15,897,000)
Share-based compensation expense	606,000	450,000	464,000	358,000	369,000	336,000
Share repurchase plan						(671,000)
Restricted Stock Units	(3,000)	(2,000)	(110,000)	(4,000)	(11,000)	(30,000)
Contributions from noncontrolling stockholders				30,000
Distributions to noncontrolling stockholders			(5,300,000)
Balance	103,573,000	117,199,000	95,749,000	90,207,000	105,585,000	117,399,000	103,573,000	90,207,000
Balance	(40,407,000)						(40,407,000)
Additional Paid-In Capital [Member]
Balance	150,780,000	150,332,000	149,979,000	149,266,000	148,908,000	148,602,000	149,979,000	148,602,000
Share-based compensation expense	606,000	450,000	464,000	358,000	369,000	336,000
Restricted Stock Units	(3,000)	(2,000)	(111,000)	(4,000)	(11,000)	(30,000)
Balance	151,383,000	150,780,000	150,332,000	149,620,000	149,266,000	148,908,000	151,383,000	149,620,000
Retained Earnings (Accumulated Deficit) [Member]
Balance	(2,886,000)	(25,588,000)	(44,553,000)	(7,931,000)	14,772,000	20,647,000	(44,553,000)	20,647,000
Net income (loss)	(10,095,000)	22,702,000	18,965,000	(19,228,000)	(22,703,000)	(5,875,000)
Balance	(12,981,000)	(2,886,000)	(25,588,000)	(27,159,000)	(7,931,000)	14,772,000	(12,981,000)	(27,159,000)
Treasury Shares [Member]
Balance	(40,407,000)	(40,407,000)	(40,407,000)	(40,407)	(40,407)	(39,737)	(40,407,000)	(39,737)
Share repurchase plan						(670)
Balance	(40,407,000)	(40,407,000)	(40,407,000)	(40,407)	(40,407)	(40,407)	(40,407,000)	(40,407)
Accumulated Other Comprehensive Income (Loss) [Member]
Balance	8,365,000	9,957,000	12,502,000	417,000	(10,290,000)	5,589,000	12,502,000	5,589,000
Other comprehensive income, net	(4,029,000)	(1,592,000)	(2,545,000)	3,587,000	10,707,000	(15,879,000)
Balance	4,336,000	8,365,000	9,957,000	4,004,000	417,000	(10,290,000)	4,336,000	4,004,000
Reading International Inc. Stockholders' Equity [Member]
Balance	116,101,000	94,543,000	77,769,000	101,593,000	113,231,000	135,349,000	77,769,000	135,349,000
Net income (loss)	(10,095,000)	22,702,000	18,965,000	(19,228,000)	(22,703,000)	(5,875,000)
Other comprehensive income, net	(4,029,000)	(1,592,000)	(2,545,000)	3,587,000	10,707,000	(15,879,000)
Share-based compensation expense	606,000	450,000	464,000	358,000	369,000	336,000
Share repurchase plan						(670,000)
Restricted Stock Units	(3,000)	(2,000)	(110,000)	(4,000)	(11,000)	(30,000)
Balance	102,580,000	116,101,000	94,543,000	86,306,000	101,593,000	113,231,000	102,580,000	86,306,000
Noncontrolling Interests [Member]
Balance	1,098,000	1,206,000	3,404,000	3,992,000	4,168,000	4,267,000	3,404,000	4,267,000
Net income (loss)	(105,000)	(108,000)	3,102,000	(124,000)	(185,000)	(81,000)
Other comprehensive income, net				3,000	9,000	(18,000)
Contributions from noncontrolling stockholders				30,000
Distributions to noncontrolling stockholders			(5,300,000)
Balance	$ 993,000	1,098,000	$ 1,206,000	3,901,000	3,992,000	4,168,000	$ 993,000	3,901,000
Class A [Member]
Balance, shares			20,098,607				20,098,607
Balance, shares	20,128,813						20,128,813
Class A [Member] | Common Stock Shares Outstanding [Member]
Balance	$ 232,000	$ 232,000	$ 231,000	$ 231,000	$ 231,000	$ 231,000	$ 231,000	$ 231,000
Balance, shares	20,125	20,121	20,069	20,068	20,047	20,103	20,069	20,103
Share repurchase plan, shares						(75)
Restricted Stock Units			$ 1,000
Restricted Stock Units, shares	2	4	52	1	21	19
Balance	$ 232,000	$ 232,000	$ 232,000	$ 231,000	$ 231,000	$ 231,000	$ 232,000	$ 231,000
Balance, shares	20,127	20,125	20,121	20,069	20,068	20,047	20,127	20,069
Class B [Member]
Balance, shares			1,680,590				1,680,590
Balance, shares	1,680,590						1,680,590
Class B [Member] | Common Stock Shares Outstanding [Member]
Balance	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000
Balance, shares	1,680	1,680	1,680	1,680	1,680	1,680	1,680	1,680
Balance	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000	$ 17,000
Balance, shares	1,680	1,680	1,680	1,680	1,680	1,680	1,680	1,680