Note 17 - Fair Values of the Company's Pension Plan Assets by Asset Category (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Equity Securities U.S. Companies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	$ 13,547	$ 14,513
Equity Securities U.S. Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
Equity Securities U.S. Companies [Member]
Fair value of plan assets	$ 13,547	$ 14,513
Equity Securities International Companies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	$ 7,377	$ 7,900
Equity Securities International Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
Equity Securities International Companies [Member]
Fair value of plan assets	$ 7,377	$ 7,900
Fixed Income Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	11,207	11,964
Fixed Income Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets	2,168	2,129
Fixed Income Funds [Member]
Fair value of plan assets	13,375	14,093
Commodities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	$ 2,962	$ 3,161
Commodities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
Commodities [Member]
Fair value of plan assets	$ 2,962	$ 3,161
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	$ 1,874	$ 1,998
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
US Treasury Securities [Member]
Fair value of plan assets	$ 1,874	$ 1,998
Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	36,967	39,536
Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets	2,168	2,129
Fair value of plan assets	$ 39,135	$ 41,665