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Short-Term and Long-Term Borrowings - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 31, 2022	Jun. 10, 2021
Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount			$ 230,000,000
Proceeds from issuance of debt	$ 140,000,000
Series 2021A Senior Unsecured Notes
Debt Instrument [Line Items]
Interest rate (as a percent)		2.74%
Series 2021A Senior Unsecured Notes | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount			$ 40,000,000
Interest rate (as a percent)			2.74%
Series 2021B Senior Unsecured Notes
Debt Instrument [Line Items]
Interest rate (as a percent)		3.69%
Series 2021B Senior Unsecured Notes | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount			$ 100,000,000
Interest rate (as a percent)			3.69%
Senior Unsecured Notes 3.77%, Series A, Due May 20, 2052 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount			$ 90,000,000
Interest rate (as a percent)			3.77%
Minimum
Debt Instrument [Line Items]
Interest and dividend coverage ratio		1.50
Maximum
Debt Instrument [Line Items]
Debt to total capitalization ratio		60.00%

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