Employee Retirement and Pension Benefits - Change in Fair Value of Plan Asset (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
U.S.
Defined Benefit Plan, Change in Fair Value of Plan Assets
Balance as of January 1,	$ 302,763	$ 339,751
Actual return on plan assets	69,767	(20,466)
Company contribution	7,760	4,125
Benefits paid	(16,751)	(15,965)
Administrative expenses paid	(4,962)	(4,682)
Balance at period end	358,577	302,763
Non U.S
Defined Benefit Plan, Change in Fair Value of Plan Assets
Balance as of January 1,	12,676	15,994
Actual return on plan assets	1,398	(33)
Company contribution	236	250
Benefits paid	(3,272)	(2,046)
Administrative expenses paid	(21)	(25)
Cumulative translation adjustment	(93)	(1,464)
Balance at period end	$ 10,924	$ 12,676