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, 2018 USD ($)	[1]	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	[1]	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue		$ 74,990		$ 74,261	$ 84,262	$ 75,872	$ 71,841		$ 66,116	$ 72,440	$ 69,481	$ 309,385	$ 279,879	$ 270,866	[2]
Cost of services and products												(244,722)	(224,456)	(214,933)
Depreciation and amortization												(22,275)	(16,942)	(15,689)	[2]
General and administrative expense												(27,337)	(25,347)	(26,906)	[2]
Total Costs and Expenses												(285,307)	(259,173)	(250,162)	[2]
Segment operating income												$ 24,078	20,706	20,704	[2]
Number of segments | segment												2
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												$ 318,412	287,452	278,232
Depreciation and amortization												(21,881)	(16,469)	(15,294)
Total Costs and Expenses												(272,653)	(246,326)	(235,412)
Segment operating income												45,759	41,126	42,820
Inter-segment Elimination [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	[3]											(9,027)	(7,573)	(7,366)
Total Costs and Expenses	[3]											9,027	7,573	7,366
Cinema [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost of services and products												(234,818)	(215,020)	(205,889)
Cinema [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												294,177	263,464	256,922
Depreciation and amortization												(16,314)	(12,213)	(11,772)
Total Costs and Expenses												(254,856)	(230,494)	(221,424)
Segment operating income												39,321	32,970	35,498
Cinema [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]											(9,027)	(7,573)	(7,366)
Real Estate [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost of services and products												(9,904)	(9,436)	(9,044)
Real Estate [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												24,235	23,988	21,310
Depreciation and amortization												(5,567)	(4,256)	(3,522)
Total Costs and Expenses												(17,797)	(15,832)	(13,988)
Segment operating income												6,438	8,156	7,322
Real Estate [Member] | Inter-segment Elimination [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	[3]											(9,027)	(7,573)	(7,366)
Segment [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
General and administrative expense												(6,050)	(5,401)	(5,185)
Segment [Member] | Cinema [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
General and administrative expense												(3,724)	(3,261)	(3,763)
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												(2,326)	(2,140)	(1,422)
Third Party [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												309,385	279,879	270,866
Cost of services and products												(235,695)	(216,883)	(207,567)
Third Party [Member] | Cinema [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												294,177	263,464	256,922
Cost of services and products												(225,791)	(207,447)	(198,523)
Third Party [Member] | Real Estate [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue												15,208	16,415	13,944
Cost of services and products												$ (9,904)	$ (9,436)	$ (9,044)

[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.