Retirement Benefit Plans - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) subsidiary employee plan	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Feb. 03, 2006 plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of non-contributory defined benefit pension plans | plan				2
Estimate of amount of unrecognized actuarial expense	$ 500
Number of defined contribution plans | plan	2
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Underfunded status	$ (1,730)	$ (1,844)
Supplemental Employee Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimate of amount of unrecognized actuarial expense	$ 700
SERP credited service period	10 years
Percentage of final 3 year average salary in which retirement benefit is based (percentage)	20.00%
Number of final years in which the Retirement Benefit is based	3 years
Retirement age	65 years
Period of time that vested retirement benefit will be paid after death or change in control	90 days
Years of monthly installments associated with SERP disability	15 years
Supplemental Employee Retirement Plan | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Current retirement benefit percentage	10.00%
Supplemental Employee Retirement Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Current retirement benefit percentage	20.00%
Employees’ Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Former employees | employee	247
Current employees | employee	55
IAM Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Annual contribution amount	$ 400	600	$ 400
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Annual contribution amount	3,500	2,800	2,300
Foreign Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Annual contribution amount	$ 900	$ 900	$ 900
Number of international subsidiaries that participate in defined contribution and savings plan | subsidiary	3
Foreign Plan | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contribution percentage	0.00%
Foreign Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contribution percentage	10.00%