Borrowings (Summary Of Borrowings) (Details) $ in Thousands, $ in Millions										9 Months Ended		12 Months Ended
		Aug. 30, 2021 NZD ($)	May 07, 2021 NZD ($)	Mar. 13, 2020 USD ($)	Mar. 12, 2020 USD ($)	Mar. 06, 2020 USD ($)	Sep. 18, 2019	Oct. 12, 2018 USD ($)	Dec. 13, 2016 USD ($)	Sep. 30, 2021 USD ($)		Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Contractual Facility										$ 269,953		$ 300,449
Balance Gross										245,753		284,959
Balance Net										242,627	[1]	282,583	[2]
Deferred financing costs, net										$ 3,100		$ 2,400
Trust Preferred Securities [Member]
Debt Instrument [Line Items]
Maturity Date										Apr. 30, 2027		Apr. 30, 2027
Contractual Facility										$ 27,913		$ 27,913
Balance Gross										27,913		27,913
Balance Net										$ 26,672	[1]	$ 26,505	[2]
Stated Interest Rate										4.13%		4.27%
Effective Interest Rate										4.13%		4.27%
Bank Of America Credit Facility [Member]
Debt Instrument [Line Items]
Maturity Date						Mar. 06, 2023				Mar. 06, 2023		Mar. 06, 2023
Contractual Facility						$ 55,000				$ 55,000		$ 55,000
Balance Gross										42,800		51,200
Balance Net										$ 42,645	[1]	$ 50,990	[2]
Stated Interest Rate										4.00%		4.00%
Effective Interest Rate										4.00%		4.00%
Bank Of America Line Of Credit [Member]
Debt Instrument [Line Items]
Maturity Date						Mar. 06, 2023				Mar. 06, 2023		Mar. 06, 2023
Contractual Facility						$ 5,000				$ 5,000		$ 5,000
Balance Gross										5,000		5,000
Balance Net										$ 5,000	[1]	$ 5,000	[2]
Stated Interest Rate										3.08%		3.15%
Effective Interest Rate										3.08%		3.15%
US Cinema 1, 2, 3 Term Loan [Member]
Debt Instrument [Line Items]
Maturity Date				Apr. 01, 2022						Apr. 01, 2022		Apr. 01, 2022
Contractual Facility				$ 25,000	$ 20,000					$ 24,189		$ 24,625
Balance Gross										24,189		24,625
Balance Net										$ 23,826	[1]	$ 24,248	[2]
Stated Interest Rate										4.25%		4.25%
Effective Interest Rate										4.25%		4.25%
Minetta And Orpheum Theatres Loan [Member]
Debt Instrument [Line Items]
Maturity Date	[3]									Nov. 01, 2023		Nov. 01, 2023
Contractual Facility								$ 7,500		$ 8,000	[3]	$ 8,000	[3]
Balance Gross	[3]									8,000		8,000
Balance Net	[3]									$ 7,936	[1]	$ 7,914	[2]
Stated Interest Rate	[3]									2.14%		2.20%
Effective Interest Rate	[3]									5.15%		5.15%
U.S. Corporate Office Term Loan [Member]
Debt Instrument [Line Items]
Maturity Date										Jan. 01, 2027		Jan. 01, 2027
Contractual Facility									$ 8,400	$ 9,000		$ 9,186
Balance Gross										9,000		9,186
Balance Net										$ 8,920	[1]	$ 9,095	[2]
Effective Interest Rate										4.61%		4.64%
Union Square Construction Financing [Member]
Debt Instrument [Line Items]
Maturity Date												Mar. 31, 2021
Contractual Facility												$ 50,000
Balance Gross												40,623
Balance Net	[2]											$ 40,620
Stated Interest Rate												17.50%
Effective Interest Rate												17.50%
Purchase Money Promissory Note [Member]
Debt Instrument [Line Items]
Maturity Date							Sep. 18, 2024			Sep. 18, 2024		Sep. 18, 2024
Contractual Facility										$ 2,216		$ 2,883
Balance Gross										2,216		2,883
Balance Net										$ 2,216	[1]	$ 2,883	[2]
Stated Interest Rate										5.00%		5.00%
Effective Interest Rate										5.00%		5.00%
US Union Square Term Loan - Sun Life [Member]
Debt Instrument [Line Items]
Maturity Date										May 06, 2024
Contractual Facility										$ 55,000
Balance Gross										43,000
Balance Net	[1]									$ 41,920
Stated Interest Rate										7.00%
Effective Interest Rate										7.00%
NAB Australian Corporate Term Loan [Member]
Debt Instrument [Line Items]
Maturity Date										Dec. 31, 2023		Dec. 31, 2023
Contractual Facility										$ 74,087		$ 94,821
Balance Gross										74,087		92,508
Balance Net										$ 73,944	[1]	$ 92,307	[2]
Stated Interest Rate										1.81%		1.81%
Effective Interest Rate										1.81%		1.81%
Westpac Bank Corporate Credit Facility [Member]
Debt Instrument [Line Items]
Maturity Date										Dec. 31, 2023		Dec. 31, 2023
Contractual Facility		$ 13.8	$ 16.0							$ 9,548		$ 23,021
Balance Gross										9,548		23,021
Balance Net										$ 9,548	[1]	$ 23,021	[2]
Stated Interest Rate										2.95%		2.95%
Effective Interest Rate										2.95%		2.95%
Minimum [Member] | U.S. Corporate Office Term Loan [Member]
Debt Instrument [Line Items]
Stated Interest Rate										4.44%		4.44%
Maximum [Member] | U.S. Corporate Office Term Loan [Member]
Debt Instrument [Line Items]
Stated Interest Rate										4.64%		4.64%

[1] Net of deferred financing costs amounting to $3.1 million.

[2] Net of deferred financing costs amounting to $2.4 million.

[3] The interest rate derivative associated with the Minetta & Orpheum loan provides for an effective fixed rate of 5.15%.