Employee Benefit Plans - Changes in Projected Benefit Obligations and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in Plan Assets
Fair value of plan assets at beginning of year	$ 844,588
Fair value of plan assets at end of year	745,858	$ 844,588
Pension
Change in Projected Benefit Obligation
Projected benefit obligation at beginning of year	1,013,541	1,112,785
Service cost	9,857	11,663	$ 5,646
Interest cost	36,138	35,499	15,926
Actuarial loss (gain)	101,576	(44,976)
Participant contributions	900	905
Benefits paid	(55,801)	(59,531)
Plan amendment	1,693	0
Settlement	(222,342)	0
Effects of foreign currency exchange rates	22,811	(42,804)
Projected benefit obligation at end of year	908,373	1,013,541	1,112,785
Change in Plan Assets
Fair value of plan assets at beginning of year	844,588	979,269
Actual return on plan assets	148,226	(44,167)
Employer contributions	8,899	9,109
Participant contributions	900	905
Benefits paid	(55,801)	(59,316)
Settlement	(222,342)	0
Effects of foreign currency exchange rates	21,388	(41,212)
Fair value of plan assets at end of year	745,858	844,588	979,269
Funded Status at end of year:	(162,515)	(168,953)
Postretirement
Change in Projected Benefit Obligation
Projected benefit obligation at beginning of year	41,243	45,449
Service cost	1,849	1,716	1,249
Interest cost	1,432	1,327	827
Actuarial loss (gain)	(39)	(2,720)
Participant contributions	130	360
Benefits paid	(2,824)	(3,418)
Plan amendment	0	0
Settlement	(146)	0
Effects of foreign currency exchange rates	926	(1,471)
Projected benefit obligation at end of year	42,571	41,243	45,449
Change in Plan Assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	2,694	3,059
Participant contributions	130	360
Benefits paid	(2,824)	(3,419)
Settlement	0	0
Effects of foreign currency exchange rates	0	0
Fair value of plan assets at end of year	0	0	$ 0
Funded Status at end of year:	$ (42,571)	$ (41,243)