Note 2 - Cash and Balances Due From Banks (Details Textual) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Cash Reserve Deposit Required and Made	$ 1,515,000	$ 1,417,000

Cash deposited in a special reserve account for the exclusive benefit of customers pursuant to SEC Regulations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 305
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6478312&loc=d3e61473-112792

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