Employee Benefits - Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable (Details) - $ / shares	12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Defined Contribution Plan Disclosure [Line Items]
Options Outstanding, Number	140,500	148,000	104,000	89,500
Options Outstanding, Weighted Average Exercise Price	$ 34.43	$ 39.63	$ 36.56	$ 33.77
Options Exercisable, Number	65,800	63,700	44,900
Options Exercisable, Weighted Average Exercise Price	$ 38.44	$ 33.89	$ 31.92
43 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	43 months
Options Outstanding, Number	11,500
Options Outstanding, Weighted Average Exercise Price	$ 37.31
Options Exercisable, Number	11,500
Options Exercisable, Weighted Average Exercise Price	$ 37.31
54 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	54 months
Options Outstanding, Number	15,500
Options Outstanding, Weighted Average Exercise Price	$ 34.35
Options Exercisable, Number	15,500
Options Exercisable, Weighted Average Exercise Price	$ 34.35
68 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	68 months
Options Outstanding, Number	15,500
Options Outstanding, Weighted Average Exercise Price	$ 37.40
Options Exercisable, Number	12,400
Options Exercisable, Weighted Average Exercise Price	$ 37.40
79 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	79 months
Options Outstanding, Number	23,000
Options Outstanding, Weighted Average Exercise Price	$ 34.91
Options Exercisable, Number	13,800
Options Exercisable, Weighted Average Exercise Price	$ 34.91
91 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	91 months
Options Outstanding, Number	11,500
Options Outstanding, Weighted Average Exercise Price	$ 53.82
Options Exercisable, Number	4,600
Options Exercisable, Weighted Average Exercise Price	$ 53.82
97 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	97 months
Options Outstanding, Number	7,500
Options Outstanding, Weighted Average Exercise Price	$ 46.59
Options Exercisable, Number	1,500
Options Exercisable, Weighted Average Exercise Price	$ 46.59
104 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	104 months
Options Outstanding, Number	32,500
Options Outstanding, Weighted Average Exercise Price	$ 46.94
Options Exercisable, Number	6,500
Options Exercisable, Weighted Average Exercise Price	$ 46.94
111 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	111 months
Options Outstanding, Number	3,500
Options Outstanding, Weighted Average Exercise Price	$ 40.28
Options Exercisable, Weighted Average Exercise Price	$ 40.28
115 mo.
Defined Contribution Plan Disclosure [Line Items]
Weighted Average Remaining Contractual Life	115 months
Options Outstanding, Number	20,000
Options Outstanding, Weighted Average Exercise Price	$ 40.82
Options Exercisable, Weighted Average Exercise Price	$ 40.82