Note 2 - Notes Payable and Long-term Debt - Summary of Credit Agreement and Line of Credit Note (Details) (Parentheticals) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Promissory Note with BOKF [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Note, Interest at LIBOR	1.85%	1.85%
Promissory Note with BOKF [Member]
Line of Credit Note, Principal Amount	$ 15,000,000	$ 15,000,000
Promissory Note and Business Loan Agreement with BOKF [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Note, Interest at LIBOR	1.85%	1.85%
Promissory Note and Business Loan Agreement with BOKF [Member]
Line of Credit Note, Principal Amount	$ 6,000,000	$ 6,000,000