Note 5 - Stock-Based Compensation (Details) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Note 5 - Stock-Based Compensation (Details) [Line Items]
Maximum Period of Common Stock Granted	10 years
Annual Increments to Be Vested in Common Stock Units	20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		0
Allocated Share-based Compensation Expense (in Dollars)	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	3,750	0
Proceeds from Stock Options Exercised (in Dollars)	88,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value (in Dollars)	10,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	37,675
Shares Available for Future Grant Calculated Based On Maximum of Earned Shares from TSR & EPS RSU	3,562,168
Restricted Stock Units (RSUs) [Member]
Note 5 - Stock-Based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	37,675	17,601
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$ 27.53	$ 24.66
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years	2 years
Stock or Unit Option Plan Expense (in Dollars)	1,100,000	1,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars)	$ 6,500,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 109 days
Performance TSR Restricted Stock [Member]
Note 5 - Stock-Based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			60,456
Performance EPS Restricted Stock Units [Member]
Note 5 - Stock-Based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			57,642

The annual increments to be vested in common stock units, as a percentage.

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The maximum period of common stock granted.

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Represents the number shares available for future grant calculated based on maximum of earned shares from TSR & EPS restricted stock units.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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Number of share options (or share units) exercised during the current period.

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