SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts
VALUATION AND QUALIFYING ACCOUNTS
Balance at the Beginning of the Period	$ 3,541	$ 3,161	$ 2,989
Charged to Costs and Expenses	782	923	235
Deductions from Reserve	(697)	(543)	(63)
Balance at the End of the Period	3,626	3,541	3,161
Deferred tax valuation allowance
VALUATION AND QUALIFYING ACCOUNTS
Balance at the Beginning of the Period	11,189	5,414	4,070
Charged to Costs and Expenses	12,058	4,230	3,640
Charged to Other Accounts	1,508	2,604
Deductions from Reserve	(1,435)	(1,059)	(2,296)
Balance at the End of the Period	$ 23,320	$ 11,189	$ 5,414