Securities, Amortized Cost and Fair Value and Allowance for Credit Loss on Securities Held-to-Maturity (Details) $ in Thousands		3 Months Ended
		Sep. 30, 2023 USD ($) Category	Jun. 30, 2023 USD ($)
Held-to-maturity securities [Abstract]
Amortized cost	[1]	$ 712,214	$ 726,363
Unrealized gains		1,945	5,178
Unrealized losses		81,996	60,475
Fair value		632,163	671,066
Allowance	[2]	498	0
Net carrying value		711,716	726,363
Accrued interest receivable		$ 4,600	3,900
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]	$ 33,726	33,705
Unrealized gains		0	0
Unrealized losses		2,525	2,438
Fair value		31,201	31,267
Allowance	[2]	0	0
Net carrying value		33,726	33,705
State and Political Subdivisions [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	467,693	478,756
Unrealized gains		1,945	5,178
Unrealized losses		48,799	30,662
Fair value		420,839	453,272
Allowance	[2]	46	0
Net carrying value		467,647	478,756
Mortgage-backed Securities-Residential [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	35,927	37,186
Unrealized gains		0	0
Unrealized losses		4,507	3,625
Fair value		31,420	33,561
Allowance	[2]	0	0
Net carrying value		35,927	37,186
Mortgage-backed Securities-Multi-family [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	152,504	155,046
Unrealized gains		0	0
Unrealized losses		23,140	20,324
Fair value		129,364	134,722
Allowance	[2]	0	0
Net carrying value		152,504	155,046
Corporate Debt Securities [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	22,327	21,632
Unrealized gains		0	0
Unrealized losses		3,025	3,426
Fair value		19,302	18,206
Allowance	[2]	451	0
Net carrying value		21,876	21,632
Other Securities [Member]
Held-to-maturity securities [Abstract]
Amortized cost	[1]	37	38
Unrealized gains		0	0
Unrealized losses		0	0
Fair value		37	38
Allowance	[2]	1	0
Net carrying value		$ 36	$ 38

[1] Amortized cost excludes accrued interest receivable of $4.6 million and $3.9 million at September 30, 2023 and June 30, 2023, respectively, which is included in accrued interest receivable in the consolidated statement of financial condition.

[2] The Company adopted ASU 2016-13 (CECL) on July 1, 2023. For periods subsequent to adoption, an allowance is calculated under the CECL methodology. The periods prior to adoption did not have an allowance for credit losses under applicable GAAP for those periods.