Other Comprehensive Income (Loss) - Other comprehensive income (loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other comprehensive income (loss), before tax amount
Other comprehensive income (loss), before tax amount	$ (918)	$ 1,051	$ (1,880)
Other comprehensive income (loss), tax (expense) benefit
Other comprehensive income (loss), tax (expense) benefit	81	(195)	124
Other comprehensive income (loss):
Total other comprehensive income (loss), net of tax	(837)	856	(1,756)
Foreign Currency Translation Adjustment
Other comprehensive income (loss), before tax amount
Other comprehensive income (loss), before reclassifications, before tax	(827)	223	(1,343)
Other comprehensive income (loss), tax (expense) benefit
Other comprehensive income (loss), before reclassifications, tax (expense) benefit	61
Other comprehensive income (loss):
Other comprehensive income (loss), before reclassifications, net of tax	(766)	223	(1,343)
Unrealized/Recognized Gains (Losses)
Other comprehensive income (loss), before tax amount
Other comprehensive income (loss), before reclassifications, before tax	(29)	1,127	(529)
Amounts reclassified from accumulated other comprehensive income (loss), before tax	(62)	(299)	(8)
Other comprehensive income (loss), tax (expense) benefit
Other comprehensive income (loss), before reclassifications, tax (expense) benefit	7	(265)	122
Amounts reclassified from accumulated other comprehensive income (loss), tax (expense) benefit	13	70	2
Other comprehensive income (loss):
Other comprehensive income (loss), before reclassifications, net of tax	(22)	862	(407)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	$ (49)	$ (229)	$ (6)