Nature of Business and Summary of Significant Accounting Policies - Intangible Assets (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023
Intangible assets
Amortization expense	$ 84,000	$ 90,000	$ 168,000	$ 181,000
Changes in intangible assets
Carrying value	13,848,000		13,848,000		$ 13,848,000
Accumulated amortization	(10,077,000)		(10,077,000)		(9,909,000)
Net book value	3,771,000		3,771,000		$ 3,939,000
Future amortization expense
2024	336,000		336,000
2025	315,000		315,000
2026	297,000		297,000
2027	283,000		283,000
2028	269,000		$ 269,000
Weighted average remaining period			15 years 1 month 6 days		15 years 6 months
Customer relationships
Changes in intangible assets
Carrying value	9,800,000		$ 9,800,000		$ 9,800,000
Accumulated amortization	(9,369,000)		(9,369,000)		(9,302,000)
Net book value	431,000		431,000		498,000
Trade name
Changes in intangible assets
Carrying value	4,048,000		4,048,000		4,048,000
Accumulated amortization	(708,000)		(708,000)		(607,000)
Net book value	$ 3,340,000		$ 3,340,000		$ 3,441,000