Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowances for Accounts Receivable
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 3,219	$ 3,705	$ 3,688
Charged to Operations	4,269	3,243	5,974
Write-Offs, Net of Recoveries	(3,467)	(3,729)	(5,957)
Other Changes	0	0	0
Balance at End of Period	4,021	3,219	3,705
Valuation Allowance for Deferred Tax Assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	37,345	1,189	1,076
Charged to Operations	118	36,224	113
Write-Offs, Net of Recoveries	0	0	0
Other Changes	9	(68)	0
Balance at End of Period	$ 37,472	$ 37,345	$ 1,189