Income tax reconciliation (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Federal rate		$ 924,000	$ 7,941,000	$ 3,226,000
State income taxes (net of Federal   income tax benefit)		(30,000)	2,634,000	1,048,000
Carryback of net operating loss	$ (1,100,000)	0	0	(1,100,000)
Other, net		121,000	(503,000)	(59,000)
Provision for income taxes		$ 1,015,000	$ 10,072,000	$ 3,115,000