Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts Receivables
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 168	$ 125
Additions Charged to Expenses or Other Accounts		43
Deductions Credited to Expenses or Other Accounts	(39)
Balance at End of Period	129	168
Deferred Tax Valuation Allowance
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	45,496	42,308
Additions Charged to Expenses or Other Accounts	(2)	3,188
Balance at End of Period	$ 45,494	$ 45,496