Defined Benefit Plans (Korea Employee Severance Plan) (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Minimum years of service		1 year
Service cost	$ 88	$ 88
Interest cost	13	13
Net cost	101	101
Employer contributions	1	1
Additional employer contributions expected to be paid during the remainder of fiscal year	$ 5	$ 5