Note 14 - Stock-based Compensation (Details) - Summary of Outstanding Stock Options (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary of Outstanding Stock Options [Abstract]
Number of Shares - Options Outstanding	1,074,552	1,134,602	1,482,077
Weighted Average Exercise Price - Options Outstanding	$ 46.44	$ 46.75	$ 46.92
Options exercisable at December 31, 2014	158,573
Options exercisable at December 31, 2014	$ 48.06
Options exercisable at December 31, 2014	$ 2,344,000
Number of Shares - Options Granted	57,716	57,672	63,516
Weighted Average Exercise Price - Options Granted	$ 53.10	$ 47.95	$ 44.28
Number of Shares - Options Exercised	(157,590)	(19,722)	(295,371)
Weighted Average Exercise Price - Options Exercised	$ 45.97	$ 45.63	$ 45.41
Number of Shares, Cancelled	(20,000)	(98,000)	(115,620)
Weighted Average Exercise Price, Cancelled	$ 46.69	$ 51.11	$ 50.99
Number of Shares - Options Outstanding	954,678	1,074,552	1,134,602
Weighted Average Exercise Price - Options Outstanding	$ 46.92	$ 46.44	$ 46.75
Aggregate Intrinsic Value - Options Outstanding	$ 15,202,000

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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

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