Debt and Credit Facilities (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended
	Oct. 20, 2022	Sep. 30, 2022	Dec. 31, 2021
Line of Credit Facility [Line Items]
Debt borrowing capacity		$ 600,000
Borrowings outstanding		573,750	$ 427,500
Line of credit borrowings outstanding		380,000
Stand-by letters of credit		$ 58,400
Wells Fargo Term Loan Mature May 14, 2024
Schedule of Capitalization, Long-Term Debt [Line Items]
Term loan maturity		May 14, 2024
Term loan outstanding amount		$ 100,000
Term loan interest rate		3.77%
BMO Harris Bank N.A. Term Loan Mature May 14, 2024
Schedule of Capitalization, Long-Term Debt [Line Items]
Term loan maturity		May 14, 2024
Term loan face amount		$ 100,000
Term loan outstanding amount		$ 93,800
Term loan interest rate		1.28%
Frequency of periodic payment		quarterly
Periodic payment, principal		$ 1,250
Wells Fargo Bank, N.A. Line of Credit Facility, Mature May 14, 2024
Line of Credit Facility [Line Items]
Debt borrowing capacity		$ 300,000
Committed credit facilities maturity		May 14, 2024
Interest rate swap facility, amount		$ 75,000
Line of credit borrowings outstanding		$ 75,000
Line of credit facility, interest rate		3.43%
Interest rate swap facility, fixed interest		2.29%
Interest rate swap facility, maturity date		May 14, 2024
Maximum limit for aggregate amount of letters of credit issued		$ 75,000
BMO Harris Bank N.A. Line of Credit Facility, Mature May 14, 2024
Line of Credit Facility [Line Items]
Debt borrowing capacity		$ 300,000	$ 200,000
Committed credit facilities maturity		May 14, 2024
Interest rate swap facility, amount		$ 75,000
Line of credit borrowings outstanding		$ 75,000
Line of credit facility, interest rate		3.45%
Interest rate swap facility, fixed interest		2.34%
Interest rate swap facility, maturity date		May 14, 2024
Debt instrument, description of variable rate basis		SOFR
Debt instrument, basis spread on variable rate		0.10%
Additional Outstanding Debt Under Credit Facilities
Line of Credit Facility [Line Items]
Line of credit borrowings outstanding		$ 230,000
Line of credit facility, interest rate		3.59%
Subsequent Event | Wells Fargo Bank, N.A. Line of Credit Facility, Mature May 14, 2024
Line of Credit Facility [Line Items]
Proceeds from issuance of long-term debt	$ 10,000
SOFR | Wells Fargo Debt Facilities
Schedule of Capitalization, Long-Term Debt [Line Items]
Debt instrument, description of variable rate basis		SOFR
Debt instrument, basis spread on variable rate		0.10%
Term SOFR | Wells Fargo Debt Facilities
Schedule of Capitalization, Long-Term Debt [Line Items]
Debt instrument description of fixed rate basis		Term SOFR
Debt instrument basis spread on fixed rate one month term		0.10%
Debt instrument basis spread on fixed rate three month term		0.15%
Debt instrument basis spread on fixed rate six month term		0.25%
Minimum | Wells Fargo Bank, N.A. Line of Credit Facility, Mature May 14, 2024
Line of Credit Facility [Line Items]
Letter of credit fee on outstanding amount, percentage		0.55%
Unused capacity commitment fee, percentage		0.11%
Minimum | BMO Harris Bank N.A. Line of Credit Facility, Mature May 14, 2024
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		0.70%
Minimum | SOFR | Wells Fargo Debt Facilities
Schedule of Capitalization, Long-Term Debt [Line Items]
Debt instrument, basis spread on variable rate		0.675%
Minimum | Term SOFR | Wells Fargo Debt Facilities
Schedule of Capitalization, Long-Term Debt [Line Items]
Debt instrument, basis spread on variable rate		0.675%
Maximum | Wells Fargo Bank, N.A. Line of Credit Facility, Mature May 14, 2024
Line of Credit Facility [Line Items]
Letter of credit fee on outstanding amount, percentage		0.80%
Unused capacity commitment fee, percentage		0.15%
Maximum | BMO Harris Bank N.A. Line of Credit Facility, Mature May 14, 2024
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		1.50%
Maximum | SOFR | Wells Fargo Debt Facilities
Schedule of Capitalization, Long-Term Debt [Line Items]
Debt instrument, basis spread on variable rate		0.925%
Maximum | Term SOFR | Wells Fargo Debt Facilities
Schedule of Capitalization, Long-Term Debt [Line Items]
Debt instrument, basis spread on variable rate		0.925%