Note 3 - Accounting Standards Adopted in Fiscal 2019 and Recent Accounting Pronouncements (Details Textual) - USD ($)	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Oct. 01, 2018
Net Income (Loss) Attributable to Parent, Total	$ (21,533,000)	$ 14,739,000
Unrealized Gain (Loss) on Investments, Total	(28,640,000)
Cumulative Effect of New Accounting Principle in Period of Adoption
AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	(115,786,000)
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent, Total	(21,533,000)	$ 14,739,000
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 115,786,000
Accounting Standards Update 2016-01 [Member] | AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ (115,786,000)
Accounting Standards Update 2016-01 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ 115,786,000