Summary Of Significant Accounting Policies (Accounting Changes To Consolidated Statements Of Operations) (Details) - USD ($)	3 Months Ended											12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Revenue	$ 71,780,000		$ 66,087,000	$ 72,413,000	$ 69,454,000	$ 67,451,000	[1]	$ 71,315,000	$ 66,918,000	$ 64,789,000		$ 279,734,000	$ 270,473,000	[2]	$ 257,865,000	[2]
Costs and expenses												(259,173,000)	(250,162,000)	[2]	(234,169,000)	[2]
Operating Income												20,561,000	20,311,000	[2]	23,696,000	[2]
Interest expense (net), casualty loss and others												12,971,000	(7,873,000)		3,279,000
Income before income taxes and earnings of unconsolidated joint ventures												33,532,000	12,438,000	[2]	26,975,000	[2]
Equity earnings of unconsolidated joint ventures												815,000	999,000	[2]	1,204,000	[2]
Income before income taxes												34,347,000	13,437,000	[2]	28,179,000	[2]
Income tax expense												(3,337,000)	(4,020,000)	[2]	(5,148,000)	[2]
Net Income	$ 7,459,000		$ 1,458,000	$ 19,052,000	$ 3,041,000	$ 354,000	[1]	$ 3,917,000	$ 2,922,000	$ 2,224,000		$ 31,010,000	$ 9,417,000	[2]	$ 23,031,000	[2]
Basic earnings per share	$ 0.33		$ 0.07	$ 0.82	$ 0.13	$ 0.01	[1]	$ 0.17	$ 0.13	$ 0.09		$ 1.35	$ 0.40	[2]	$ 0.99	[2]
Diluted earnings per share	$ 0.32		$ 0.07	$ 0.81	$ 0.13	$ 0.02	[1]	$ 0.16	$ 0.13	$ 0.09		$ 1.33	$ 0.40	[2]	$ 0.98	[2]
Without Breakage Revenue [Member]
Revenue												$ 279,126,000	$ 269,855,000
Costs and expenses												(259,173,000)	(250,162,000)
Operating Income												19,953,000	19,693,000
Interest expense (net), casualty loss and others												12,971,000	(7,873,000)
Income before income taxes and earnings of unconsolidated joint ventures												32,924,000	11,820,000
Equity earnings of unconsolidated joint ventures												815,000	999,000
Income before income taxes												33,739,000	12,819,000
Income tax expense												(3,098,000)	(3,787,000)
Net Income												$ 30,641,000	$ 9,032,000
Basic earnings per share												$ 1.33	$ 0.39
Diluted earnings per share												$ 1.32	$ 0.38
Previously Reported [Member]
Revenue															$ 257,323,000
Costs and expenses															(234,169,000)
Operating Income															23,154,000
Interest expense (net), casualty loss and others															3,279,000
Income before income taxes and earnings of unconsolidated joint ventures															26,433,000
Equity earnings of unconsolidated joint ventures															1,204,000
Income before income taxes															27,637,000
Income tax expense															(4,943,000)
Net Income															$ 22,694,000
Basic earnings per share															$ 0.98
Diluted earnings per share															$ 0.97
Adjustment [Member]
Revenue												$ 608,000	$ 618,000		$ 542,000
Operating Income												608,000	618,000		542,000
Income before income taxes and earnings of unconsolidated joint ventures												608,000	618,000		542,000
Income before income taxes												608,000	618,000		542,000
Income tax expense						$ 611,000					$ 514,000	(239,000)	(233,000)		(205,000)
Net Income												$ 369,000	$ 385,000		$ 337,000
Basic earnings per share												$ 0.02	$ 0.01		$ 0.01
Diluted earnings per share												$ 0.02	$ 0.02		$ 0.01

[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).