Description Of Business And Segment Reporting (Summary Of Results Of Operations For Principal Business Segments) (Details) $ in Thousands		3 Months Ended										12 Months Ended
		Dec. 31, 2017 USD ($)	[1]	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	[1]	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)		Dec. 31, 2015 USD ($)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue		$ 71,780		$ 66,087	$ 72,413	$ 69,454	$ 67,451		$ 71,315	$ 66,918	$ 64,789	$ 279,734	$ 270,473	[2]	$ 257,865	[2]
Cost of services and products												(224,456)	(214,933)		(207,492)
Depreciation and amortization												(16,942)	(15,689)	[2]	(14,562)	[2]
General and administrative expense												(25,347)	(26,906)	[2]	(18,652)	[2]
Total Costs and Expenses												(259,173)	(250,162)	[2]	(234,169)	[2]
Segment operating income												$ 20,561	20,311	[2]	23,696	[2]
Number of segments | segment												2
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												$ 287,307	277,839		264,402
Depreciation and amortization												(16,469)	(15,294)		(14,268)
Total Costs and Expenses												(246,326)	(235,412)		(225,488)
Segment operating income												40,981	42,427		38,914
Inter-segment Elimination [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	[3]											(7,573)	(7,366)		(6,537)
Total Costs and Expenses	[3]											7,573	7,366		6,537
Cinema Exhibition [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost of services and products												(215,020)	(205,889)		(196,544)
Cinema Exhibition [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												263,464	256,922		242,823
Depreciation and amortization												(12,213)	(11,772)		(11,161)
Total Costs and Expenses												(230,494)	(221,424)		(210,705)
Segment operating income												32,970	35,498		32,118
Cinema Exhibition [Member] | Inter-segment Elimination [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost of services and products	[3]											(7,573)	(7,366)		(6,537)
Real Estate [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost of services and products												(9,436)	(9,044)		(10,948)
Real Estate [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												23,843	20,917		21,579
Depreciation and amortization												(4,256)	(3,522)		(3,107)
Total Costs and Expenses												(15,832)	(13,988)		(14,783)
Segment operating income												8,011	6,929		6,796
Real Estate [Member] | Inter-segment Elimination [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	[3]											(7,573)	(7,366)		(6,537)
Segment [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
General and administrative expense												(5,401)	(5,185)		(3,728)
Segment [Member] | Cinema Exhibition [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
General and administrative expense												(3,261)	(3,763)		(3,000)
Segment [Member] | Real Estate [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
General and administrative expense												(2,140)	(1,422)		(728)
Third Party [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												279,734	270,473		257,865
Cost of services and products												(216,883)	(207,567)		(200,955)
Third Party [Member] | Cinema Exhibition [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												263,464	256,922		242,823
Cost of services and products												(207,447)	(198,523)		(190,007)
Third Party [Member] | Real Estate [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												16,270	13,551		15,042
Cost of services and products												$ (9,436)	$ (9,044)		$ (10,948)

[1] Net income for the 4th quarter of 2017 includes approximately $2.5 million net tax benefit from non-recurring items of tax benefit and expense related to the Tax Cuts and Jobs Act enacted December 2017 and dissolution of a non-operating foreign subsidiary.

[2] Certain prior year balances have been reclassified to conform to the 2017 presentation (see Note 2 - Summary of Significant Accounting Policies - Reclassifications).

[3] Inter-segment Revenues and Cost of services relates to the internal charge between the two segments where the cinema operates within real estate owned within the group.