Schedule II. - VALUATION AND QUALIFYING ACCOUNTS (Details) - Allowance for doubtful accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Valuation and Qualifying Accounts
Balance at beginning of year	$ 111	$ 100	$ 245
Charged to cost and expenses	245	159	189
Deductions	(174)	(148)	(334)
Balance at end of year	$ 182	$ 111	$ 100