Schedule Of Valuation And Qualifying Accounts (Tables) (Details) - Allowance for doubtful accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 3,417	$ 2,943	$ 338
Charges to Operatons	0	499	2,639
Other additions	0	0	0
Deductions	579	25	34
Balance at end of period	$ 2,838	$ 3,417	$ 2,943