Derivatives (Fair Value Of Derivative Instruments And Locations In Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 12,870	$ 721
Non-current derivative assets	0	0
Total derivatives assets	12,870	721
Current derivative liabilities	0	7,763
Non-current derivative liabilities	293	0
Total derivative liabilities	$ 293	$ 7,763