Employee Benefits - Information Related to Changes in Projected Benefit Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at beginning of year	$ 45,450	$ 38,400	$ 35,870
Service cost	3,145	2,820	2,780
Interest cost	840	765	850
Actuarial loss (gain) due to assumption changes and plan experience	(430)	690	1,480
Additions and contractual termination benefits	(950)	(860)	0
Benefits paid	(1,400)	(920)	(1,640)
Foreign currency impact	(1,765)	4,555	(940)
Projected benefit obligation at end of year	$ 44,890	$ 45,450	$ 38,400