SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Additions Charged to Cost and Expenses	$ (482)	$ (3,950)	$ (13,028)
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	8	23	33
Additions Charged to Cost and Expenses	16	0	0
Deductions	0	(15)	(10)
Balance at End of Year	24	8	23
Deferred tax asset valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	38,839	34,889	21,861
Additions Charged to Cost and Expenses	481	3,950	13,028
Deductions	0	0	0
Balance at End of Year	$ 39,320	$ 38,839	$ 34,889