Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net periodic benefit cost [Abstract]
Total amount amortized out of accumulated other comprehensive income	$ 2,552	$ 856		$ 7,587	$ 2,574
Defined contribution plan expense	12,530	12,188	$ 38,340	39,071
Post-Retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	5	5		15	15
Interest cost	60	78		181	234
Prior service cost (credit)	3	3		10	10
Recognized actuarial loss	(3)	(17)		(11)	(52)
Net periodic (income)/expense	65	69		195	207
Qualified Plan [Member] | Defined benefit pension plans | United States
Net periodic benefit cost [Abstract]
Service cost	1,706	1,754		5,118	5,262
Interest cost	4,068	4,756		12,204	14,269
Expected return on plan assets	(7,869)	(8,534)		(23,607)	(25,602)
Prior service cost (credit)	57	76		170	227
Recognized actuarial loss	1,884	0		5,652	0
Net periodic (income)/expense	(154)	(1,948)		(463)	(5,844)
Qualified Plan [Member] | Defined benefit pension plans | Foreign Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	1,366	1,429		3,954	4,265
Interest cost	839	1,193		2,460	3,641
Expected return on plan assets	(1,719)	(1,538)		(5,033)	(4,664)
Prior service cost (credit)	(126)	(102)		(365)	(298)
Recognized actuarial loss	777	763		2,253	2,288
Net periodic (income)/expense	1,137	1,745		3,269	5,232
Nonqualified Plan [Member] | Supplemental Employee Retirement Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	318	486		954	1,457
Interest cost	441	668		1,324	2,003
Prior service cost (credit)	424	703		1,271	2,109
Recognized actuarial loss	(464)	(570)		(1,393)	(1,710)
Net periodic (income)/expense	$ 719	$ 1,287		$ 2,156	$ 3,859