Non-controlling Interests (Summary Of Changes In Controlling And Non-controlling Stockholders’ Equity) (Details) - USD ($)	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
Balance			$ (39,737,000)				$ (39,737,000)
Balance	$ 105,585,000	$ 117,399,000	139,616,000	$ 177,023,000	$ 179,335,000	$ 179,979,000	139,616,000	$ 179,979,000
Net income (loss)	(19,352,000)	(22,888,000)	(5,956,000)	801,000	2,294,000	(2,140,000)	(48,195,000)	954,000
Other comprehensive income, net	3,590,000	10,716,000	(15,897,000)	417,000	(2,347,000)	1,511,000
Share-based compensation expense	358,000	369,000	336,000	(8,690,000)	400,000	280,000
Share repurchase plan	0	0	(671,000)		(2,622,000)	(9,000)
Class A common stock issued for share-based bonuses and options exercised						(185,000)
In-kind exchange of share for the exercise of options, net issued				(22,000)
Restricted Stock Units	(4,000)	(11,000)	(30,000)		(31,000)	(74,000)
Contributions from noncontrolling stockholders	30,000			28,000	9,000	18,000
Distributions to noncontrolling stockholders					(15,000)	(27,000)
Balance	90,207,000	105,585,000	117,399,000	162,988,000	177,023,000	179,335,000	90,207,000	162,988,000
Balance	(40,407,000)						(40,407,000)
Additional Paid-In Capital [Member]
Balance	149,266,000	148,908,000	148,602,000	147,841,000	147,472,000	147,452,000	148,602,000	147,452,000
Other comprehensive income, net				417,000
Share-based compensation expense	358,000	369,000	336,000		400,000	280,000
Class A common stock issued for share-based bonuses and options exercised						(185,000)
In-kind exchange of share for the exercise of options, net issued				(22,000)
Restricted Stock Units	(4,000)	(11,000)	(30,000)		(31,000)	(75,000)
Balance	149,620,000	149,266,000	148,908,000	148,236,000	147,841,000	147,472,000	149,620,000	148,236,000
Retained Earnings (Accumulated Deficit) [Member]
Balance	(7,931,000)	14,772,000	20,647,000	47,283,000	44,952,000	47,048,000	20,647,000	47,048,000
Net income (loss)	(19,228,000)	(22,703,000)	(5,875,000)	851,000	2,331,000	(2,124,000)
Balance	(27,159,000)	(7,931,000)	14,772,000	48,134,000	47,283,000	44,952,000	(27,159,000)	48,134,000
Treasury Shares [Member]
Balance	(40,407,000)	(40,407,000)	(39,737,000)	(27,853)	(25,231)	$ (25,222)	(39,737,000)	(25,222)
Share-based compensation expense				$ (8,690)
Share repurchase plan	0	0	(670,000)		(2,622)
Share repurchase plan, shares						(9)
Restricted Stock Units, shares				2
Balance	(40,407,000)	(40,407,000)	(40,407,000)	$ (36,541)	(27,853)	$ (25,231)	(40,407,000)	(36,541)
Accumulated Other Comprehensive Income/(Loss) [Member]
Balance	417,000	(10,290,000)	5,589,000	5,279,000	7,625,000	6,115,000	5,589,000	6,115,000
Other comprehensive income, net	3,587,000	10,707,000	(15,879,000)		(2,346,000)	1,510,000
Balance	4,004,000	417,000	(10,290,000)	(1,288,000)	5,279,000	7,625,000	4,004,000	(1,288,000)
Reading International Inc. Stockholders' Equity [Member]
Balance	101,593,000	113,231,000	135,349,000	172,800,000	175,068,000	175,642,000	135,349,000	175,642,000
Net income (loss)	(19,228,000)	(22,703,000)	(5,875,000)	851,000	2,331,000	(2,124,000)
Other comprehensive income, net	3,587,000	10,707,000	(15,879,000)	417,000	(2,346,000)	1,510,000
Share-based compensation expense	358,000	369,000	336,000	(8,690,000)	400,000	280,000
Share repurchase plan	0	0	(670,000)		(2,622,000)	(9,000)
Class A common stock issued for share-based bonuses and options exercised						(185,000)
In-kind exchange of share for the exercise of options, net issued				(22,000)
Restricted Stock Units	(4,000)	(11,000)	(30,000)		(31,000)	(74,000)
Balance	86,306,000	101,593,000	113,231,000	158,789,000	172,800,000	175,068,000	86,306,000	158,789,000
Noncontrolling Interests [Member]
Balance	3,992,000	4,168,000	4,267,000	4,223,000	4,267,000	4,337,000	4,267,000	4,337,000
Net income (loss)	(124,000)	(185,000)	(81,000)	(50,000)	(37,000)	(16,000)
Other comprehensive income, net	3,000	9,000	(18,000)		(1,000)	1,000
Contributions from noncontrolling stockholders	30,000			28,000	9,000	18,000
Distributions to noncontrolling stockholders					(15,000)	(27,000)
Balance	$ 3,901,000	3,992,000	$ 4,168,000	4,199,000	4,223,000	4,267,000	$ 3,901,000	4,199,000
Accounting Standards Update 2016-02 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance					(18,000)
Balance				(6,569,000)		(18,000)		(6,569,000)
Accounting Standards Update 2016-02 [Member] | Retained Earnings (Accumulated Deficit) [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance					28,000
Balance						28,000
Accounting Standards Update 2016-02 [Member] | Accumulated Other Comprehensive Income/(Loss) [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				(6,567,000)				(6,567,000)
Accounting Standards Update 2016-02 [Member] | Reading International Inc. Stockholders' Equity [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance					28,000
Balance				(6,567,000)		28,000		(6,567,000)
Accounting Standards Update 2016-02 [Member] | Noncontrolling Interests [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance					(46,000)
Balance				(2,000)		(46,000)		(2,000)
Class A [Member]
Balance, shares			20,102,535				20,102,535
Balance, shares	20,068,607						20,068,607
Class A [Member] | Common Stock Shares Outstanding [Member]
Balance	$ 231,000	$ 231,000	$ 231,000	$ 233,000	$ 233,000	$ 232,000	$ 231,000	$ 232,000
Balance, shares	20,068	20,047	20,103	21,071	21,235	21,195	20,103	21,195
Share-based compensation expense, shares				(660)
Share repurchase plan, shares			(75)		(197)
In-kind exchange of share for the exercise of options, net issued, shares				(6)
Restricted Stock Units				$ (2,000)		$ 1,000
Restricted Stock Units, shares	1	21	19		33	40
Balance	$ 231,000	$ 231,000	$ 231,000	$ 231,000	$ 233,000	$ 233,000	$ 231,000	$ 231,000
Balance, shares	20,069	20,068	20,047	20,405	21,071	21,235	20,069	20,405
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