Related Parties (Narrative) (Details) - USD ($)					12 Months Ended
		Aug. 31, 2016	Jan. 01, 2015	Jun. 28, 2007	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2012	Feb. 28, 2015
Related Party Transaction [Line Items]
Total operating property					$ 257,667,000	$ 264,724,000
Current capital lease liability	[1]				5,900,000	5,900,000
Contributions from noncontrolling stockholders					82,000	193,000	$ 268,000
Renovation amount					149,734,000	153,232,000
Contractual facility					252,929,000	271,732,000
Capital call					0	0	506,000
US Cinema 1, 2, 3 Term Loan [Member]
Related Party Transaction [Line Items]
Contractual facility		$ 15,000,000			$ 19,086,000	19,500,000	20,000,000
Shadow View Land And Farming, LLC [Member]
Related Party Transaction [Line Items]
Noncontrolling interests					50.00%
Cinemas 1, 2, 3 [Member]
Related Party Transaction [Line Items]
Improvement fee					$ 528,000	0	0
Management fee								$ 177,000
Incremental positive cash flow percentage			100.00%
Average annual positive cash flow period			3 years
Annual cash-on-cash return percent			15.00%
Sutton Hill Capital, LLC [Member]
Related Party Transaction [Line Items]
Related party expense					$ 590,000	590,000	590,000
Lease term					10 years
Lease expiration date					Jun. 30, 2020
Purchase option					$ 5,900,000
Total operating property					4,700,000
Current capital lease liability					$ 5,900,000
Payment to acquire interest in special purpose entity				$ 3,000,000
Debt amount				26,900,000
Due from related party				$ 2,900,000
Renovation amount										$ 750,000
Capital call							169,000
Guarantee and indemnity percentage					25.00%
Sutton Hill Capital, LLC [Member] | Cinemas 1, 2, 3 [Member]
Related Party Transaction [Line Items]
Percent of management fee equal to SHP's gross income					5.00%
Sutton Hill Capital's Interest In Sutton Hill Properties [Member]
Related Party Transaction [Line Items]
Special purpose entity purchase option, percentage					25.00%
OBI Management [Member]
Related Party Transaction [Line Items]
Estimated related party expense							79,000
Historical related party fees paid as percentage of cash flow received from certain theaters					21.00%
James Cotter And Michael Forman [Member]
Related Party Transaction [Line Items]
Ownership percentage in live theater play investment					5.00%
Chief Executive Officer [Member]
Related Party Transaction [Line Items]
Contributions from noncontrolling stockholders									$ 2,500,000
Bonus contributed to acquire land									$ 255,000
Chief Executive Officer [Member] | Shadow View Land And Farming, LLC [Member]
Related Party Transaction [Line Items]
Noncontrolling interests									50.00%
Cinema Ground Lease [Member]
Related Party Transaction [Line Items]
Lease expiration date					Jun. 01, 2031
86th Street Cinema [Member]
Related Party Transaction [Line Items]
Management fee					$ 172,000	$ 141,000	$ 150,000
Minimum [Member]
Related Party Transaction [Line Items]
Lease term					1 year
Minimum [Member] | Sutton Hill Capital, LLC [Member]
Related Party Transaction [Line Items]
Purchase option					$ 100,000
Sutton Hill Properties, LLC [Member] | US Cinema 1, 2, 3 Term Loan [Member]
Related Party Transaction [Line Items]
Contractual facility		$ 15,000,000

[1] Represents the lease liability of the option associated with the ground lease purchase of the Village East Cinema. See below for more information.