Investments (Narrative) (Details) - USD ($)	3 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Schedule of Investments [Line Items]
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	$ 23,600,000		$ 23,500,000
Certificates of deposit, at carrying value	0
Non-governmental issues exceeding 10% shareholders equity threshold	0		0
Allowance for credit loss	0		0
Credit-related investment impairment losses	0	$ 0
Asset Pledged as Collateral
Schedule of Investments [Line Items]
Carrying value of securities pledged	760,000,000		709,000,000
Marketable equity securities
Schedule of Investments [Line Items]
Investment securities	$ 7,200,000		$ 7,500,000