Income Taxes - Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of the beginning and ending amount of unrecognized tax benefits:
Balance, beginning of year	$ 2,314	$ 2,125
Additions based on tax positions related to prior years	0	247
Settlements with taxing authorities	(2,173)	(58)
Balance, end of year	141	2,314
Total amount of tax benefits that if recognized would favorable impact the effective tax rate	136	2,200
Settlements with taxing authorities	141
Interest and penalties accrued	$ 34	$ 470