Note 13 - Stock Based Compensation (Detail) - Stock Compensation Plans (USD $)	9 Months Ended
Sep. 30, 2012
Balance, January 1, 2012	228,070
Balance, January 1, 2012 (in Dollars per share)	$ 26.76
Balance, January 1, 2012	127,217
Balance, January 1, 2012 (in Dollars per share)	$ 26.49
Granted	51,245
Granted (in Dollars per share)	$ 26.29
Stock Awards Vested	(42,613)
Stock Awards Vested (in Dollars per share)	$ 28.25
Forfeited/Expired	(400)
Forfeited/Expired (in Dollars per share)	$ 26.20
Balance, September 30, 2012	227,670
Balance, September 30, 2012 (in Dollars per share)	$ 26.76
Balance, September 30, 2012	135,849
Balance, September 30, 2012 (in Dollars per share)	$ 25.92
Exercisable, September 30, 2012	218,356
Exercisable, September 30, 2012 (in Dollars per share)	$ 26.61

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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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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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.

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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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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including 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 grantees could have acquired the underlying shares with respect to stock options that were terminated.

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