Note 5 - Investments in Affordable Housing and Alternative Energy Partnerships - Investments in Affordable Housing and Alternative Energy Partnerships (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Investments in affordable housing partnerships, net	$ 287,517	$ 279,981
Other borrowings for affordable housing limited partnerships	23,145	23,714
Investments in affordable housing and alternative energy partnerships, unfunded commitments	107,652	103,060
Investments in alternative energy tax credit partnerships, net	$ 11,694	$ 29,035