Retirement Plans - Summary of Reconciliation of Benefit Obligation, Plan Assets, and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in plan assets:
Beginning Balance	$ 282,696
Ending Balance	287,270	$ 282,696
Post-Retirement Life Insurance Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	5,376	4,766
Change in projected benefit obligation:
Beginning Balance	4,766	4,595
Service cost	1	1	$ 2
Interest cost	122	170	156
Benefits paid	(154)	(145)
Actuarial loss	641	145
Ending Balance	5,376	4,766	4,595
Change in plan assets:
Beginning Balance	0	0
Actual return on assets	0	0
Company contributions	154	145
Benefits paid	(154)	(145)
Foreign exchange impact	0	0
Ending Balance	0	0	0
Funded status (plan assets less projected benefit obligations)	(5,376)	(4,766)
United States
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	230,205	220,339
Change in projected benefit obligation:
Beginning Balance	220,339	205,319
Service cost	0	0	0
Interest cost	5,773	7,724	7,123
Benefits paid	(14,590)	(14,834)
Actuarial loss	18,683	22,130
Foreign exchange impact	0	0
Ending Balance	230,205	220,339	205,319
Change in plan assets:
Beginning Balance	281,276	258,327
Actual return on assets	18,886	37,680
Company contributions	103	103
Benefits paid	(14,590)	(14,834)
Foreign exchange impact	0	0
Ending Balance	285,675	281,276	258,327
Funded status (plan assets less projected benefit obligations)	55,470	60,937
Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	1,983	1,854
Change in projected benefit obligation:
Beginning Balance	2,633	2,756
Service cost	31	37	43
Interest cost	28	31	42
Benefits paid	(285)	(408)
Actuarial loss	95	153
Foreign exchange impact	184	64
Ending Balance	2,686	2,633	2,756
Change in plan assets:
Beginning Balance	1,419	1,425
Actual return on assets	95	73
Company contributions	268	295
Benefits paid	(285)	(408)
Foreign exchange impact	98	34
Ending Balance	1,595	1,419	$ 1,425
Funded status (plan assets less projected benefit obligations)	$ (1,091)	$ (1,214)