Note 10 - Reserves - Allowance for Doubtful Accounts and Reserves for Environmental Liabilities (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Balance at beginning of year	$ 194	$ 163
Increase	$ 125	$ 31
Decrease
Balance at end of year	$ 319	$ 194