Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Changes in accumulated other comprehensive income, net of tax
Balance at December 31, 2016			$ (2,279)
Other comprehensive income	$ 556	$ 962	3,017	$ 1,607
Balance at September 30, 2017	738		738
Foreign currency
Changes in accumulated other comprehensive income, net of tax
Balance at December 31, 2016			(1,591)
Other comprehensive income			2,928
Balance at September 30, 2017	1,337		1,337
Defined benefit pension plan
Changes in accumulated other comprehensive income, net of tax
Balance at December 31, 2016			(688)
Other comprehensive income			89
Balance at September 30, 2017	$ (599)		$ (599)