Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current taxes:
US Federal	$ 1,122	$ 6,765	$ 12,015
State and local	662	1,136	2,564
Foreign	4,578	3,313	3,821
Total current taxes	6,362	11,214	18,400
Deferred taxes:
US Federal	7,569	314	(3,331)
State and local	22	36	(156)
Foreign	(49)	(201)	202
Total deferred taxes	7,542	149	(3,285)
Income tax expense (benefit)	$ 13,904	$ 11,363	$ 15,115