Summary Of Significant Accounting Policies (Narrative) (Details) $ in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($)	Dec. 31, 2020 USD ($) a segment	Dec. 31, 2020 AUD ($) segment	Dec. 31, 2020 NZD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Restricted cash, Current		$ 8,000			$ 7,000,000,000
Number of operating segments | segment		2	2	2
Derivative position		$ 430,000			342,000
Impairment of long-lived assets		217,000
Goodwill impairment		0			0	$ 0
Advertising expense		700,000			1,800,000	2,400,000
Gains/(losses) on the settlement of litigation		3,000			(67,000)	0
Non Income Producing Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived assets		$ 217,000			$ 0	$ 0
Mt. Gravatt [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage		33.30%
Rialto Cinemas [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage		50.00%
Australia [Member]
Summary Of Significant Accounting Policies [Line Items]
Subsidies received		$ 9,500,000	$ 12.3
New Zealand [Member]
Summary Of Significant Accounting Policies [Line Items]
Subsidies received		$ 1,400,000		$ 1.9
Australia Country Cinemas, Pty Ltd [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage by parent		75.00%
Sutton Hill Properties, LLC [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage by parent		75.00%
Shadow View Land And Farming, LLC [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage by parent		50.00%
Area of property | a		202
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage		20.00%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage		50.00%
Tax Year 2019 [Member]
Summary Of Significant Accounting Policies [Line Items]
Prior period immaterial error amount	$ 993,000