Pension and Other Postretirement Benefits - Funded Status Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	$ 144,241
Fair Value of Plan Assets at End of Year	315,649	$ 144,241
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Non-current Asset	0	3,656
Current Liabilities	(3,405)	(1,211)
Non-current Liabilities	(56,828)	(32,360)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation at Beginning of Year	170,050	181,329
Service Cost	3,941	3,809
Interest Cost	6,359	4,101
Employee Contributions	73	73
Effect of Plan Amendments	30	0
Plan Settlements	(1,087)	(10)
Benefits Paid	(9,866)	(5,969)
Plan Expenses and Premiums Paid	(129)	(161)
Transfer In of Business Acquisition	172,072	0
Actuarial (gain) Loss	24,478	(7,704)
Translation Difference and Other	5,695	(5,418)
Benefit Obligation at End of Year	371,616	170,050	$ 181,329
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	144,241	150,586
Actual Return on Plan Assets	24,121	(2,213)
Employer Contributions	6,310	6,843
Employee Contributions	73	73
Plan Settlements	(1,087)	(10)
Benefits Paid	(9,866)	(5,969)
Plan Expenses and Premiums Paid	(629)	(411)
Transfer In of Business Acquisition	146,987	0
Translation Difference	5,499	(4,658)
Fair Value of Plan Assets at End of Year	315,649	144,241	150,586
Defined Benefit Plan, Funded Status of Plan	(55,967)	(25,809)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Non-current Asset	0	3,656
Current Liabilities	(2,979)	(765)
Non-current Liabilities	(52,988)	(28,700)
Net Amount Recognized	(55,967)	(25,809)
Amounts Not Yet Reflected in Net Periodic Benefit Costs and Included in Accumulated Other Comprehensive Income (Loss) [Abstract]
Prior Service credit (cost)	1,271	1,497
Accumulated Loss	(69,376)	(45,399)
Accumulated Other Comprehensive Loss ("AOCI")	(68,105)	(43,902)
Cumulative Employer Contributions In Excess Of (or Below) Net Periodic Benefit Cost	12,138	18,093
Net Amount Recognized	(55,967)	(25,809)
Domestic plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	49,415
Fair Value of Plan Assets at End of Year	120,550	49,415
Domestic plan [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation at Beginning of Year	58,734	62,977
Service Cost	434	383	337
Interest Cost	3,313	1,847	1,932
Employee Contributions	0	0
Effect of Plan Amendments	0	0
Plan Settlements	0	0
Benefits Paid	(6,034)	(4,330)
Plan Expenses and Premiums Paid	0	0
Transfer In of Business Acquisition	86,414	0
Actuarial (gain) Loss	10,862	(2,143)
Translation Difference and Other	0	0
Benefit Obligation at End of Year	153,723	58,734	62,977
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	49,415	51,964
Actual Return on Plan Assets	10,663	457
Employer Contributions	1,087	1,574
Employee Contributions	0	0
Plan Settlements	0	0
Benefits Paid	(6,034)	(4,330)
Plan Expenses and Premiums Paid	(500)	(250)
Transfer In of Business Acquisition	65,919	0
Translation Difference	0	0
Fair Value of Plan Assets at End of Year	120,550	49,415	51,964
Defined Benefit Plan, Funded Status of Plan	(33,173)	(9,319)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Non-current Asset	0	3,656
Current Liabilities	(2,620)	(559)
Non-current Liabilities	(30,553)	(12,416)
Net Amount Recognized	(33,173)	(9,319)
Amounts Not Yet Reflected in Net Periodic Benefit Costs and Included in Accumulated Other Comprehensive Income (Loss) [Abstract]
Prior Service credit (cost)	0	0
Accumulated Loss	(46,560)	(25,310)
Accumulated Other Comprehensive Loss ("AOCI")	(46,560)	(25,310)
Cumulative Employer Contributions In Excess Of (or Below) Net Periodic Benefit Cost	13,387	15,991
Net Amount Recognized	(33,173)	(9,319)
Domestic plan [Member] | Other Postretirement Benefit Plans Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation at Beginning of Year	4,106	4,729
Service Cost	6	7	8
Interest Cost	143	130	144
Employee Contributions	0	0
Effect of Plan Amendments	0	0
Plan Settlements	0	0
Benefits Paid	(384)	(317)
Plan Expenses and Premiums Paid	0	0
Transfer In of Business Acquisition	0	0
Actuarial (gain) Loss	395	(443)
Translation Difference and Other	0	0
Benefit Obligation at End of Year	4,266	4,106	4,729
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	0	0
Actual Return on Plan Assets	0	0
Employer Contributions	384	317
Employee Contributions	0	0
Plan Settlements	0	0
Benefits Paid	(384)	(317)
Plan Expenses and Premiums Paid	0	0
Transfer In of Business Acquisition	0	0
Translation Difference	0	0
Fair Value of Plan Assets at End of Year	0	0	0
Defined Benefit Plan, Funded Status of Plan	(4,266)	(4,106)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Non-current Asset	0	0
Current Liabilities	(426)	(446)
Non-current Liabilities	(3,840)	(3,660)
Net Amount Recognized	(4,266)	(4,106)
Amounts Not Yet Reflected in Net Periodic Benefit Costs and Included in Accumulated Other Comprehensive Income (Loss) [Abstract]
Prior Service credit (cost)	0	0
Accumulated Loss	(734)	(338)
Accumulated Other Comprehensive Loss ("AOCI")	(734)	(338)
Cumulative Employer Contributions In Excess Of (or Below) Net Periodic Benefit Cost	(3,532)	(3,768)
Net Amount Recognized	(4,266)	(4,106)
Foreign [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	94,826
Fair Value of Plan Assets at End of Year	195,099	94,826
Foreign [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation at Beginning of Year	111,316	118,352
Service Cost	3,507	3,426	3,219
Interest Cost	3,046	2,254	2,066
Employee Contributions	73	73
Effect of Plan Amendments	30	0
Plan Settlements	(1,087)	(10)
Benefits Paid	(3,832)	(1,639)
Plan Expenses and Premiums Paid	(129)	(161)
Transfer In of Business Acquisition	85,658	0
Actuarial (gain) Loss	13,616	(5,561)
Translation Difference and Other	5,695	(5,418)
Benefit Obligation at End of Year	217,893	111,316	118,352
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	94,826	98,622
Actual Return on Plan Assets	13,458	(2,670)
Employer Contributions	5,223	5,269
Employee Contributions	73	73
Plan Settlements	(1,087)	(10)
Benefits Paid	(3,832)	(1,639)
Plan Expenses and Premiums Paid	(129)	(161)
Transfer In of Business Acquisition	81,068	0
Translation Difference	5,499	(4,658)
Fair Value of Plan Assets at End of Year	195,099	94,826	$ 98,622
Defined Benefit Plan, Funded Status of Plan	(22,794)	(16,490)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Non-current Asset	0	0
Current Liabilities	(359)	(206)
Non-current Liabilities	(22,435)	(16,284)
Net Amount Recognized	(22,794)	(16,490)
Amounts Not Yet Reflected in Net Periodic Benefit Costs and Included in Accumulated Other Comprehensive Income (Loss) [Abstract]
Prior Service credit (cost)	1,271	1,497
Accumulated Loss	(22,816)	(20,089)
Accumulated Other Comprehensive Loss ("AOCI")	(21,545)	(18,592)
Cumulative Employer Contributions In Excess Of (or Below) Net Periodic Benefit Cost	(1,249)	2,102
Net Amount Recognized	$ (22,794)	$ (16,490)