Short-Term Borrowings (Details) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 28, 2021	Mar. 31, 2022	Dec. 31, 2021
Short-term Debt [Line Items]
Ratio of Indebtedness to Net Capital		0.65
Notional Amount of Nonderivative Instruments	$ 40,000,000	$ 30,000,000
Line of Credit Facility, Remaining Borrowing Capacity		256,300,000
Short-term borrowing		$ 140,865,000	$ 221,634,000
Short-term Debt, Weighted Average Interest Rate, at Point in Time		1.17%	0.83%
Draws on letters of credit		$ 5,300,000
Financing Receivable, Revolving		400,000,000
Revolving Line of Credit, Short-term
Short-term Debt [Line Items]
Financing Receivable, Revolving		$ 200,000,000
Debt Instrument, Interest Rate, Stated Percentage		70.00%
Revolving Line of Credit, Long-term
Short-term Debt [Line Items]
Financing Receivable, Revolving		$ 200,000,000
Debt Instrument, Fee		0.09
Debt Instrument, Interest Rate, Stated Percentage		95.00%
3.48% note, due May 31, 2038 [Member]
Short-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.48%
Committed Line of Credit Facility Two [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		LIBOR rate, plus 0.75 percent
Committed Line of Credit Facility Three [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		Lender's base rate, plus 0.75 percent
Committed Line of Credit Facility Five [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		Lender's base rate, plus 0.85 percent
Committed Line of Credit Facility Four [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		LIBOR rate, plus 1.125 percent
Committed Line of Credit Facility Six [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		LIBOR rate, plus 1.75 percent
Committed Line of Credit Facility Seven [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		LIBOR rate, plus 1.75 percent
Committed Line of Credit Facility Eight [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		LIBOR rate, plus 1.75 percent
Committed Line of Credit Facility Nine [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		LIBOR rate, plus 1.75 percent
Committed Line of Credit Facility One [Member]
Short-term Debt [Line Items]
Debt Instrument, Description of Variable Rate Basis		LIBOR rate, plus 0.75 percent
Revolving Credit Facility
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 400,000,000
Interest Rate Swap Rate, Low Range [Member]
Short-term Debt [Line Items]
Fixed Swap Rate			0.20%
Interest Rate Swap Rate, High Range [Member]
Short-term Debt [Line Items]
Fixed Swap Rate		0.17%	0.205%