Income taxes, Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income taxes [Abstract]
Unrecognized tax benefits that would favorably affect effective income tax rate if recognized	$ 107	$ 104
Unrecognized tax benefits [Roll Forward]
Unrecognized tax benefits, beginning of period	104	104
Tax positions taken during the current period	28	28
Lapse of statute of limitations	(25)	(28)
Unrecognized tax benefits, end of period	107	104
Expected decrease in unrecognized tax benefits in next year	27
Accrued interest and penalties related to uncertain tax positions	$ 18	$ 17