Securities, Amortized Cost and Fair Value and Allowance for Credit Loss on Securities Held-to-Maturity (Details) $ in Thousands		3 Months Ended
		Sep. 30, 2024 USD ($) Category	Jun. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)
Held-to-maturity securities [Abstract]
Amortized cost	[1]	$ 702,385	$ 690,837
Unrealized gains		10,256	4,604
Unrealized losses		47,767	65,200
Fair value		664,874	630,241
Allowance		466	483	$ 498	$ 0
Net carrying value		701,919	690,354
Accrued interest receivable		$ 4,800	$ 4,100
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]		Interest Receivable	Interest Receivable
Number of categories utilized under risk management approach of diversified investing | Category		3
U.S. Treasury Securities [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	$ 23,803	$ 23,785
Unrealized gains		0	0
Unrealized losses		1,146	1,749
Fair value		22,657	22,036
Allowance		0	0
Net carrying value		23,803	23,785
State and Political Subdivisions [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	451,322	450,343
Unrealized gains		9,720	4,541
Unrealized losses		29,377	40,235
Fair value		431,665	414,649
Allowance		42	44
Net carrying value		451,280	450,299
Mortgage-backed Securities-Residential [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	59,045	48,033
Unrealized gains		488	51
Unrealized losses		2,196	3,314
Fair value		57,337	44,770
Allowance		0	0
Net carrying value		59,045	48,033
Mortgage-backed Securities-Multi-family [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	142,867	143,363
Unrealized gains		0	0
Unrealized losses		12,694	17,397
Fair value		130,173	125,966
Allowance		0	0
Net carrying value		142,867	143,363
Corporate Debt Securities [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	25,318	25,282
Unrealized gains		48	12
Unrealized losses		2,354	2,505
Fair value		23,012	22,789
Allowance		423	438
Net carrying value		24,895	24,844
Other Securities [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	30	31
Unrealized gains		0	0
Unrealized losses		0	0
Fair value		30	31
Allowance		1	1
Net carrying value		$ 29	$ 30

[1] Amortized cost excludes accrued interest receivable of $4.8 million and $4.1 million at September 30, 2024 and June 30, 2024, respectively, which is included in accrued interest receivable in the consolidated statement of financial condition.