Note 7 - Subordinated Debentures - Summary of Subordinated Debentures (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Variable Interest Rate Subordinated Debentures Due in 2035 [Member]
Principal amount	$ 5,155,000	$ 5,155,000
6.75% Subordinated Notes Due in 2025 [Member]
Principal amount	10,000,000	10,000,000	$ 10,000,000
Unamortized debt issuance costs	(196,000)	(206,000)
Principal amount	15,155,000	15,155,000
Unamortized debt issuance costs	$ (196,000)	$ (206,000)

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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