Pension and Other Postretirement Benefit Plans (Changes in the pension benefit obligation and plan assets) (Details) - USD ($) $ in Thousands	8 Months Ended			12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in plan assets:
Company contributions		$ 6
Swiss Pension Plan
Change in benefit obligation:
Benefit obligation at beginning of year				$ 30,257	$ 33,153
Service cost				982	1,171	$ 958
Interest cost				230	246	332
Plan participant contributions				527	509
Benefits paid				(1,729)	(1,570)
Actuarial (gain) loss				119	(2,425)
Effect of foreign currency translation				1,330	(827)
Projected benefit obligation at end of year	$ 31,716	31,716	$ 31,716	31,716	30,257	33,153
Changes in plan assets:
Fair value of plan assets at beginning of year				39,144	39,002
Actual return on plan assets				3,131	1,657
Company contributions				615	596
Plan participant contributions				527	509
Benefits paid				(1,729)	(1,570)
Effect of foreign currency translation				1,740	(1,050)
Fair value of plan assets at end of year	43,428	43,428	43,428	43,428	39,144	$ 39,002
Funded status at end of year	(11,712)	(11,712)	(11,712)	(11,712)	$ (8,887)
Korea Defined Benefit Plan
Change in benefit obligation:
Benefit obligation at beginning of year			3,360
Service cost	361		361
Interest cost	55		55
Benefits paid			(212)
Actuarial (gain) loss			174
Effect of foreign currency translation			228
Projected benefit obligation at end of year	3,966	3,966	3,966	3,966
Changes in plan assets:
Fair value of plan assets at end of year	24	24	24	24
Funded status at end of year	$ 3,942	$ 3,942	$ 3,942	$ 3,942