Contract Balances (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Period	$ 43,233
Current Period Provision For Expected Credit Losses	19,014
Write-offs Charged Against Allowance	(27,692)
Balance at End of Period	$ 34,555
Remaining performance obligations	true