Pension and Other Post-Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
U.S. Pension and Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 281	$ 447	$ 562	$ 894
Expected return on plan assets	(518)	(573)	(1,037)	(1,324)
Amortization of prior service cost	1	2,496	3	2,497
Recognized actuarial loss	75	83	149	165
Net (benefit) cost	(161)	2,453	(323)	2,232
Non-U.S. Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	204	279	408	563
Expected return on plan assets	(266)	(280)	(529)	(566)
Amortization of prior service cost	143	12	286	24
Recognized actuarial loss	13	131	24	269
Net (benefit) cost	$ 94	$ 142	$ 189	$ 290