Note 6 - Allowances for Loan and Lease Losses and Real Estate Losses - Allowance for Losses on Real Estate Owned (Details) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance—beginning of year	$ 459,000	$ 4,268,000	$ 6,575,000
Provisions for estimated losses	137,000	311,000	47,000
Losses charged off	(455,000)	(4,120,000)	(2,354,000)
Balance—end of year	$ 141,000	$ 459,000	$ 4,268,000

For each period for which an income statement is required, disclosure of the changes in the allowance, including balances at end of period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the valuation allowance for real estate owned that was applied in the period against the carrying amount of real estate owned that was sold, written down or written off.

+ References

+ Details

Name:	us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense recognized in the income statement for a decrease in valuation of real estate owned (REO).

+ References

+ Details

Name:	us-gaap_RealEstateOwnedValuationAllowanceProvision1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration