Note 8 - Pension Plan Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Insurance General Account [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Insurance General Account [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 17,918	$ 18,598
Insurance General Account [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Insurance General Account [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 17,918	$ 18,598
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 1,273
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets		$ 2,319
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Cash and Cash Equivalents [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 1,273	$ 2,319
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 37,621
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets		$ 42,608
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Equity Securities [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 37,621	$ 42,608
Fixed Income Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 9,924
Fixed Income Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets		$ 3,288
Fixed Income Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Fixed Income Securities [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 9,924	$ 3,288
Real Estate [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,510
Real Estate [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Real Estate [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,510
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	51,328
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 17,918	$ 66,813
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Defined Benefit Plan, Fair Value of Plan Assets	$ 69,246	$ 66,813