Note 15 - Supplemental Cash Flow Information (Details Textual) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock Repurchased During Period, Shares	27,770	14,571	20,256
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	279,766	309,230
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	81,608	50,224	40,816