Note 4 - Supplemental Cash Flow Information (Details Textual) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Income Taxes Paid	$ 3,173,000	$ 2,928,000
Interest Paid	$ 278,000	$ 228,000
Company Stock Received in Lieu of Cash Stock Options Exercised	10,434	7,765
Stock Issued During Period, Shares, New Issues	30,416	27,432