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
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 4,813	$ 4,471	$ 2,553
Charged to Costs and Expenses	1,481	588	1,441
Net (Deductions) Recoveries	(1,113)	(246)	477
Balance at End of Period	5,181	4,813	4,471
Deferred tax asset valuation allowance
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	445	3,994	356
Charged to Costs and Expenses			3,638
Net (Deductions) Recoveries	26	(3,549)
Balance at End of Period	471	445	3,994
Reserve for obsolete or slow moving inventory
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	10,169	3,875	3,052
Charged to Costs and Expenses	6,467	8,088	5,869
Net (Deductions) Recoveries	(6,169)	(1,794)	(5,046)
Balance at End of Period	$ 10,467	$ 10,169	$ 3,875