Note 3 - Loans Held for Investment (Details Textual) $ in Millions	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Financing Receivable, Unamortized Purchase Premium (Discount)	$ 58.8	$ 67.6
Loans and Leases Receivable, Number of Loans	47	48
Risk Rating 3 [Member]
Loans and Leases Receivable, Number of Loans	47	48

Amount of unamortized purchase premium (discount) on financing receivable. Excludes financing receivable covered under loss sharing agreement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5074-111524

Name:	us-gaap_FinancingReceivableUnamortizedPurchasePremiumDiscount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant