Note 9 - Cash Dividends (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Oct. 31, 2017
Payments of Ordinary Dividends, Common Stock	$ 1,286,000	$ 1,256,000	$ 1,286,000	$ 1,256,000
Dividends Accrued	$ 29,106	$ 13,898
Subsequent Event [Member]
Quarterly Indicated Per Share Dividend Rate					$ 0.05
Annual Indicated per Share Dividend Rate					$ 0.20

Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

Name:	us-gaap_PaymentsOfDividendsCommonStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration