Note 3 - Loans Held for Investment - Principal Balance and Net Book Value of the Loan Portfolio Based on Internal Risk Ratings (Details) $ in Thousands		Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Loan count		47	48
Carrying Value	[1]	$ 1,024,345	$ 1,045,891
% of loan portfolio		100.00%	100.00%
Risk Rating 1 [Member]
Loan count		0	0
Carrying Value		$ 0	$ 0
% of loan portfolio		0.00%	0.00%
Risk Rating 2 [Member]
Loan count		0	0
Carrying Value		$ 0	$ 0
% of loan portfolio		0.00%	0.00%
Risk Rating 3 [Member]
Loan count		47	48
Carrying Value		$ 1,024,345	$ 1,045,891
% of loan portfolio		100.00%	100.00%
Risk Rating 4 [Member]
Loan count		0	0
Carrying Value		$ 0	$ 0
% of loan portfolio		0.00%	0.00%
Risk Rating 5 [Member]
Loan count		0	0
Carrying Value		$ 0	$ 0
% of loan portfolio		0.00%	0.00%

[1] Carrying value includes the outstanding face amount plus unamortized purchase premiums/discounts and any allowance for loan losses.