Debt - Credit Facilities and Working Capital Loans (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Current maturities of long-term debt	$ 200,000	$ 200,000
Long-term debt	400,000	700,000
Short-term debt	1,400,000	1,100,000
Line of Credit
Line of Credit Facility [Line Items]
Unsecured line of credit - maximum	150,000,000.0	150,000,000.0
Long-term line of credit	0	0
Amount of letters of credit outstanding	7,600,000	8,300,000
Line of credit, additional borrowing capacity	142,400,000	141,700,000
Letter of Credit
Line of Credit Facility [Line Items]
Unsecured line of credit - maximum	30,000,000.0	30,000,000.0
Secured Debt
Line of Credit Facility [Line Items]
Current maturities of long-term debt	200,000	200,000
Long-term debt	$ 400,000	700,000
Interest rate range	10.37%
Foreign Line of Credit
Line of Credit Facility [Line Items]
Unsecured line of credit - maximum	$ 7,300,000	7,100,000
Long-term line of credit	12,800,000	9,800,000
Amount of letters of credit outstanding	2,600,000	3,500,000
Available credit line	11,400,000	8,400,000
Short-term debt	$ 1,400,000	$ 1,100,000
Minimum | Secured Debt
Line of Credit Facility [Line Items]
Interest rate range		9.50%
Minimum | Foreign Line of Credit
Line of Credit Facility [Line Items]
Interest rate range	2.40%
Maximum
Line of Credit Facility [Line Items]
Amount of letters of credit outstanding	$ 7,300,000
Maximum | Secured Debt
Line of Credit Facility [Line Items]
Interest rate range		16.33%
Maximum | Foreign Line of Credit
Line of Credit Facility [Line Items]
Interest rate range	6.75%	9.75%