Short-Term Borrowings (Details) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Feb. 28, 2021	Jun. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2021
Short-term Debt [Line Items]
Line of Credit Facility, Commitment Fee Percentage			15.00%
Ratio of Indebtedness to Net Capital		0.65	0.65
Debt Instrument, Description of Variable Rate Basis			100.00%
Notional Amount of Nonderivative Instruments	$ 40,000,000	$ 100,000,000		$ 60,000,000
Line of Credit Facility, Maximum Borrowing Capacity		375,000,000	$ 375,000,000
Line of Credit Facility, Remaining Borrowing Capacity					$ 200,900,000
Short-term borrowing		$ 169,294,000	$ 169,294,000	$ 175,644,000
Short-term Debt, Weighted Average Interest Rate, at Point in Time		1.11%	1.11%	1.28%
Draws on letters of credit			$ 4,800,000
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	$ 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%	0.17%	0.205%