Basis Of Presentation Accounts Receivables Table (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and other receivables, net of allowance for doubtful accounts and sales returns of $3,109 in 2018 and $3,304 in 2017	$ 130,551	$ 120,135