Pension Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	345	434	1,036	1,302
Return on assets (expected)	(62)	(224)	(186)	(672)
Amortization of net actuarial loss(gain)	253	138	759	414
Net periodic pension cost	536	348	1,609	1,044
Non-U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	158	154	475	462
Interest cost	101	113	303	339
Return on assets (expected)	(68)	(75)	(205)	(225)
Amortization of net actuarial loss(gain)	0	0	0	0
Net periodic pension cost	$ 191	$ 192	$ 573	$ 576