Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - 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]
Balance at beginning of period		$ 802	$ 470	$ 1,037
Charged to bad debt expense		534	552	(235)
Charged to other accounts		0	0	0
Deductions	[1]	(19)	(220)	(332)
Balance at end of period		$ 1,317	$ 802	$ 470

[1] Deductions represent the actual write-off of accounts receivable balances.