Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Components of comprehensive income
Net income	$ 9,324	$ 6,101	$ 5,544	$ 9,902	$ 6,033	$ 5,128	$ 20,969	$ 21,063
Mark to market of foreign exchange hedges				(39)			1	(33)
Deferred income tax benefit				8				7
Comprehensive income	$ 9,324	$ 6,108	$ 5,538	$ 9,871	$ 6,058	$ 5,108	$ 20,970	$ 21,037
Foreign exchange hedges liabilities									$ (1)