Income Taxes - Reconciliation of Unrecognized Tax Benefits (Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits as of January 1	$ 494	$ 469
Gross increase in unrecognized tax benefits - prior year tax positions	1,524	0
Gross increase in unrecognized tax benefits - current year tax positions	78	75
Lapse of statute of limitations	(199)	(50)
Unrecognized tax benefits as of December 31	$ 1,897	$ 494