Note 4 - Supplemental Cash Flow Information (Details Textual) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Income Taxes Paid	$ 3,927,000	$ 5,274,000
Interest Paid	$ 512,000	$ 357,000
Company Stock Received in Lieu of Cash Stock Options Exercised	12,598	14,571
Stock Issued During Period, Shares, New Issues	35,984	50,224