Note 6 - Stock-based Compensation (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	274,746	274,746	274,746	274,746
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value (in Dollars)	$ 3.8
Common Class A [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	0	0
Restricted Stock [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	150,308	312,961
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	197,858	202,743
Restricted Stock [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	150,308	312,961
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period		68,991
Restricted Stock [Member] | Common Class A [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	287,513	236,294
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	117,293	31,821
Restricted Stock [Member] | Common Class A [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	229,322	194,413
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period		31,821
Restricted Stock [Member] | Director [Member] | Common Class A [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	58,191	41,881
Directors' Restricted Stock Plan [Member] | Restricted Stock [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0	0
January 31, 2016 [Member] | Restricted Stock [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	50,102
January 31, 2016 [Member] | Restricted Stock [Member] | Common Class A [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	76,442
January 31, 2016 [Member] | Restricted Stock [Member] | Common Class A [Member] | Director [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	58,191
January 31, 2017 [Member] | Restricted Stock [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	50,100
January 31, 2017 [Member] | Restricted Stock [Member] | Common Class A [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	76,442
January 31, 2018 [Member] | Restricted Stock [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	50,106
January 31, 2018 [Member] | Restricted Stock [Member] | Common Class A [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	76,438
January 17, 2015 [Member] | Restricted Stock [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		127,316
January 17, 2015 [Member] | Restricted Stock [Member] | Common Class A [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		75,412
January 17, 2017 [Member] | Restricted Stock [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		58,327
January 17, 2017 [Member] | Restricted Stock [Member] | Common Class A [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		43,590
January 17, 2016 [Member] | Restricted Stock [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		58,327
January 17, 2016 [Member] | Restricted Stock [Member] | Common Class A [Member] | Employee [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		43,590