Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($)	Common Stock [Member]	Treasury Stock, Common [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Sep. 30, 2022	1,805,053	(428,027)
Balance at Sep. 30, 2022	$ 18,000	$ (4,000)	$ 1,755,000	$ 177,248,000	$ 179,017,000
Net income (loss)				17,827,000	17,827,000
Net income				17,827,000	17,827,000
Balance (in shares) at Dec. 31, 2022	1,805,053	(428,027)
Balance at Dec. 31, 2022	$ 18,000	$ (4,000)	1,755,000	195,075,000	196,844,000
Balance (in shares) at Sep. 30, 2022	1,805,053	(428,027)
Balance at Sep. 30, 2022	$ 18,000	$ (4,000)	1,755,000	177,248,000	179,017,000
Net income (loss)					27,260,000
Net income					27,260,000
Balance (in shares) at Mar. 31, 2023	1,805,053	(428,027)
Balance at Mar. 31, 2023	$ 18,000	$ (4,000)	1,755,000	204,508,000	206,277,000
Balance (in shares) at Dec. 31, 2022	1,805,053	(428,027)
Balance at Dec. 31, 2022	$ 18,000	$ (4,000)	1,755,000	195,075,000	196,844,000
Net income (loss)	0	0	0	9,433,000	9,433,000
Net income	$ 0	$ 0	0	9,433,000	9,433,000
Balance (in shares) at Mar. 31, 2023	1,805,053	(428,027)
Balance at Mar. 31, 2023	$ 18,000	$ (4,000)	1,755,000	204,508,000	206,277,000
Balance (in shares) at Sep. 30, 2023	1,805,053	(428,027)
Balance at Sep. 30, 2023	$ 18,000	$ (4,000)	1,755,000	198,700,000	200,469,000
Net income (loss)	0	0	0	12,615,000	12,615,000
Net income	$ 0	$ 0	0	12,615,000	12,615,000
Balance (in shares) at Dec. 31, 2023	1,805,053	(428,027)
Balance at Dec. 31, 2023	$ 18,000	$ (4,000)	1,755,000	211,315,000	213,084,000
Balance (in shares) at Sep. 30, 2023	1,805,053	(428,027)
Balance at Sep. 30, 2023	$ 18,000	$ (4,000)	1,755,000	198,700,000	200,469,000
Net income (loss)					28,030,000
Net income					28,030,000
Balance (in shares) at Mar. 31, 2024	1,805,053	(428,027)
Balance at Mar. 31, 2024	$ 18,000	$ (4,000)	1,755,000	226,730,000	228,499,000
Balance (in shares) at Dec. 31, 2023	1,805,053	(428,027)
Balance at Dec. 31, 2023	$ 18,000	$ (4,000)	1,755,000	211,315,000	213,084,000
Net income (loss)	0	0	0	15,415,000	15,415,000
Net income	$ 0	$ 0	0	15,415,000	15,415,000
Balance (in shares) at Mar. 31, 2024	1,805,053	(428,027)
Balance at Mar. 31, 2024	$ 18,000	$ (4,000)	$ 1,755,000	$ 226,730,000	$ 228,499,000