Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current income taxes:
Current income taxes, U.S. Federal		$ (1,932)	$ 0	$ 1,829
Current income taxes, State and local		67	47	27
Current income taxes, Foreign		3,032	2,852	2,226
Total current income taxes		1,167	2,899	4,082
Deferred income taxes:
Deferred income taxes, U.S. Federal		(295)	(1,289)	841
Deferred income taxes, State and local	$ 1,200	(28)	(1,144)	99
Deferred income taxes, Foreign		14	35	912
Total deferred income taxes		(309)	(2,398)	1,852
Total income taxes		$ 858	$ 501	$ 5,934