Goodwill And Intangible Assets (Summary Of Intangible Assets Other Than Goodwill) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 37,094	$ 37,253
Less: Accumulated amortization	(29,289)	(28,711)
Net intangible assets other than goodwill	7,805	8,542
Beneficial Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	28,702	28,860
Less: Accumulated amortization	(23,728)	(23,292)
Net intangible assets other than goodwill	4,974	5,568
Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	7,255	7,254
Less: Accumulated amortization	(5,072)	(4,936)
Net intangible assets other than goodwill	2,183	2,318
Other Amortization [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,137	1,139
Less: Accumulated amortization	(489)	(483)
Net intangible assets other than goodwill	$ 648	$ 656