Valuation and Qualifying Account - Allowance for Doubtful Accounts (Details) - SEC Schedule, 12-09, Allowance, Credit Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 311	$ 309	$ 395
Credited to Costs and Expenses	0	100	132
Deductions	(17)	98	218
Balance at End of Period	328	311	309
Net allowance increase during period	28
Amounts written-off as uncollectible	$ 11	$ 98	$ 218