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Note 12 - Share-based Compensation (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Number Of Active Stock Incentive Plans	1
Number Of Inactive Stock Option Plans	1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	0		0	0
Common Stock, Capital Shares Reserved for Future Issuance	557,098
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 0		$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	0
Restricted Stock Units and Performance Share Award Target Level, Percentage	100.00%
Minimum Performance Awards Issued Multiplier	0.00%
Maximum Performance Awards Issued Multiplier	200.00%
Director [Member]
Share-based Goods and Nonemployee Services Transaction, Quantity of Securities Issued	27,640		10,464	9,150
Share Based Compensation Arrangement by Stock Based Payment Award Grant Date Fair Value	$ 9.95		$ 21.02
Director [Member] | Minimum [Member]
Share Based Compensation Arrangement by Stock Based Payment Award Grant Date Fair Value				$ 36
Director [Member] | Maximum [Member]
Share Based Compensation Arrangement by Stock Based Payment Award Grant Date Fair Value				36.41
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock Units and Performance Stock Awards [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 1,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number At Target Level Of Performance	47,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 9.50		$ 0	$ 41.76
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	169,583	[1]	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 100,000		$ 1,600,000	$ 3,500,000
[1] The number of shares disclosed in this table are at the target level of 100%.

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