Debt and Financing Arrangements (Details)	Jul. 03, 2020	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Unsecured local credit facilities
Line of Credit Facility [Line Items]
Weighted average interest rate		0.28%	2.00%
Available borrowings		$ 50,300,000
Other short-term borrowings, outstanding borrowings		8,800,000	$ 2,800,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Outstanding borrowings		$ 15,900,000	0
Weighted average interest rate		1.79%
Available borrowings		$ 376,000,000.0
Letters of credit outstanding		8,100,000
Unamortized fees and expenses		700,000
Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	0.15%
Revolving Credit Facility | Maximum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	0.30%
Letters of Credit
Line of Credit Facility [Line Items]
Outstanding borrowings		11,800,000	11,700,000
Line of credit secured		8,600,000	$ 8,300,000
Maximum commitment		$ 53,700,000
Bridge Loan | Fed Funds Effective Rate Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Variable rate of interest	0.50%
Line of Credit
Line of Credit Facility [Line Items]
Initial commitment fee rate	0.20%
Secured leverage ratio	3.50
Increase in leverage ratio	3.75
Interest coverage ratio	3.00
Line of Credit | Minimum
Line of Credit Facility [Line Items]
Variable rate of interest	0.00%
Line of Credit | Maximum
Line of Credit Facility [Line Items]
Variable rate of interest	0.75%
Line of Credit | Canadian Dollar Offered Rate Cdor
Line of Credit Facility [Line Items]
Variable rate of interest	1.00%
Line of Credit | Canadian Dollar Offered Rate Cdor | Minimum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	1.00%
Line of Credit | Canadian Dollar Offered Rate Cdor | Maximum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	1.75%