Subordinated Deferrable Debt (Details) - USD ($) $ in Thousands	1 Months Ended					3 Months Ended	9 Months Ended
	Apr. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Nov. 30, 2025	Oct. 31, 2025	Feb. 28, 2026	Feb. 28, 2026	Feb. 28, 2025	Mar. 20, 2026	May 31, 2025
Long-term debt
Subordinated debt, noncurrent						$ 1,209,713	$ 1,209,713			$ 1,329,485
Redemption amount							300,150	$ 0
Proceeds from issuance of subordinated debt							179,381	$ 35,277
Retail Investors in Capital Markets
Long-term debt
Proceeds from issuance of subordinated debt							$ 29,000
Debt instrument, term							30 years
Subordinated Deferrable Notes With Variable Interest Rates Due 2043
Long-term debt
Redemption amount			$ 250,000		$ 50,000
Debt instrument, face amount					$ 300,000
Subordinated Deferrable Notes With Variable Interest Rates Due 2043 | Debt Instrument, Redemption, Period Two
Long-term debt
Losses on early extinguishment of debt						$ 2,000	$ 3,000
5.25% Fixed-to-floating Rate Subordinated Deferrable Debt Due 2046 | Subsequent Event
Long-term debt
Debt instrument, face amount									$ 350,000
Subordinated borrowing, interest rate		5.25%
Fixed-To-Fixed Reset Rate Subordinated Notes Due 2056
Long-term debt
Debt instrument, face amount				$ 600,000
Subordinated borrowing, interest rate							5.75%
Proceeds from issuance of subordinated debt							$ 150,000
Fixed-To-Fixed Reset Rate Subordinated Notes Due 2056 | Noncallable Period One
Long-term debt
Debt instrument, face amount				$ 150,000
Subordinated borrowing, noncallable period				5 years
Fixed-To-Fixed Reset Rate Subordinated Notes Due 2056 | Noncallable Period Two
Long-term debt
Debt instrument, face amount				$ 450,000
Subordinated borrowing, noncallable period				10 years
Fixed-To-Fixed Reset Rate Subordinated Notes Due 2056 | Subsequent Event | Forecast
Long-term debt
Proceeds from issuance of subordinated debt	$ 450,000