Debt and Financing Arrangements (Details)	Jul. 03, 2020 USD ($)	Apr. 01, 2020 USD ($)	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Line of Credit Facility [Line Items]
Proceeds from revolving credit facility		$ 200,000,000.0
Unsecured Local Credit Facilities
Line of Credit Facility [Line Items]
Weighted average interest rate									2.37%	2.29%
Available borrowings									$ 59,300,000
Other short-term borrowings, outstanding borrowings									6,800,000	$ 3,800,000
Subsequent Event | Base Rate | Minimum
Line of Credit Facility [Line Items]
Variable rate of interest	0.00%
Subsequent Event | Base Rate | Maximum
Line of Credit Facility [Line Items]
Variable rate of interest	1.50%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Outstanding borrowings									$ 173,800,000	$ 50,300,000
Weighted average interest rate									1.46%	3.54%
Available borrowings									$ 219,600,000
Revolving Credit Facility | Letters of Credit
Line of Credit Facility [Line Items]
Outstanding borrowings									6,600,000
Revolving Credit Facility | Subsequent Event
Line of Credit Facility [Line Items]
Maximum commitment	$ 150,000,000.0
Revolving credit facility term	364 days
Letters of Credit
Line of Credit Facility [Line Items]
Outstanding borrowings									10,300,000	$ 14,800,000
Maximum commitment									60,100,000	59,800,000
Line of credit secured									$ 7,100,000	$ 11,600,000
Letters of Credit | Forecast
Line of Credit Facility [Line Items]
Secured leverage ratio			3.50	4.00	4.50	6.50	6.50	5.50
Letters of Credit | Subsequent Event
Line of Credit Facility [Line Items]
Secured leverage ratio	3.50
Leverage ratio basis spread	0.75%
Revolving credit facility aggregate principal amount	$ 225,000,000.0
Net average secured leverage ratio	2.25
Letters of Credit | Subsequent Event | Minimum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	0.15%
Letters of Credit | Subsequent Event | Maximum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	0.45%
Letters of Credit | Subsequent Event | Weighted Average
Line of Credit Facility [Line Items]
Leverage ratio basis spread	0.30%
Letters of Credit | Subsequent Event | CDOR | Minimum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	1.00%
Variable rate of interest	1.00%
Letters of Credit | Subsequent Event | CDOR | Maximum
Line of Credit Facility [Line Items]
Leverage ratio basis spread	1.75%
Variable rate of interest	2.50%
Letters of Credit | Subsequent Event | Base Rate | Minimum
Line of Credit Facility [Line Items]
Variable rate of interest	0.00%
Letters of Credit | Subsequent Event | Base Rate | Maximum
Line of Credit Facility [Line Items]
Variable rate of interest	0.75%