Overview and Summary Of Significant Accounting Policies Schedule of Accounts and notes receivable (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables from Customers	$ 84,477		$ 91,335
Unbilled Receivables, Current	66,530		72,334
Accounts Receivable, Related Parties	0		490
Other Receivables	9,508		4,189
Accounts Receivable, Allowance for Credit Loss	(1,553)		(3,155)
Accounts Receivable, after Allowance for Credit Loss, Current	158,962		165,193
Accounts Receivable, Allowance for Credit Loss, Current	1,553	$ 4,053	$ 3,155	$ 921
Accounts Receivable, Credit Loss Expense (Reversal)	1,030	4,312
Accounts Receivable, Allowance for Credit Loss, Writeoff	(3,741)	(3,697)
Accounts Receivable, Allowance for Credit Loss, Recovery	$ 1,109	$ 2,517