Property And Equipment (Schedule Of Components Of Property And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,313,948	$ 1,233,887
Less: accumulated depreciation and amortization	(486,677)	(418,652)
Property and equipment, net	827,271	815,235
Plant Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	911,097	884,738
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	168,309	167,842
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	92,321	92,154
Railroad Track and Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	34,404	34,163
Construction-in-Progress [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	60,262	8,491
Computer Hardware And Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	19,368	18,444
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	3,716	3,639
Leasehold Improvements And Other [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 24,471	$ 24,416