Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Net periodic benefit cost [Abstract]
Total amount amortized out of accumulated other comprehensive income	$ 2,515	$ 766		$ 5,037	$ 1,718
Defined contribution plan expense	12,493	13,247	$ 26,153	26,541
Post-Retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	5	5		10	10
Interest cost	61	78		121	156
Prior service cost (credit)	4	3		7	7
Recognized actuarial loss	(4)	(16)		(8)	(35)
Net periodic (income)/expense	66	70		130	138
Qualified Plan [Member] | Defined benefit pension plans | United States
Net periodic benefit cost [Abstract]
Service cost	1,706	1,754		3,412	3,508
Interest cost	4,068	4,756		8,136	9,513
Expected return on plan assets	(7,869)	(8,534)		(15,738)	(17,068)
Prior service cost (credit)	57	76		114	151
Recognized actuarial loss	1,884	0		3,768	0
Net periodic (income)/expense	(154)	(1,948)		(308)	(3,896)
Qualified Plan [Member] | Defined benefit pension plans | Foreign Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	1,295	1,291		2,588	2,836
Interest cost	796	1,207		1,621	2,448
Expected return on plan assets	(1,637)	(1,608)		(3,314)	(3,126)
Prior service cost (credit)	(120)	(138)		(239)	(196)
Recognized actuarial loss	735	708		1,476	1,525
Net periodic (income)/expense	1,069	1,460		2,132	3,487
Nonqualified Plan [Member] | Supplemental Employee Retirement Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	318	486		636	971
Interest cost	442	668		883	1,335
Prior service cost (credit)	424	703		848	1,406
Recognized actuarial loss	(465)	(570)		(929)	(1,140)
Net periodic (income)/expense	$ 719	$ 1,287		$ 1,438	$ 2,572