Note 13 - Stock Based Compensation (Details) - Stock Options Oustanding by Range of Exercise Prices (USD $)	3 Months Ended
Mar. 31, 2015
Range01 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 24.50
Range of Exercise Prices - Upper limit	$ 24.50
Number of shares outstanding (in Shares)	15,250
Options outstanding weighted average remaining contractual life (Years)	54 days
Options outstanding weighted average exercise price	$ 24.50
Number of shares exercisable (in Shares)	15,250
Options exercisable weighted average exercise price	$ 24.50
Range 02 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 26.19
Range of Exercise Prices - Upper limit	$ 27.67
Number of shares outstanding (in Shares)	30,600
Options outstanding weighted average remaining contractual life (Years)	1 year 47 days
Options outstanding weighted average exercise price	$ 26.21
Number of shares exercisable (in Shares)	30,600
Options exercisable weighted average exercise price	$ 26.21
Range 03 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 28.42
Range of Exercise Prices - Upper limit	$ 28.42
Number of shares outstanding (in Shares)	32,300
Options outstanding weighted average remaining contractual life (Years)	2 years 58 days
Options outstanding weighted average exercise price	$ 28.42
Number of shares exercisable (in Shares)	32,300
Options exercisable weighted average exercise price	$ 28.42
Range 04 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 30.31
Range of Exercise Prices - Upper limit	$ 30.31
Number of shares outstanding (in Shares)	31,130
Options outstanding weighted average remaining contractual life (Years)	3 years 58 days
Options outstanding weighted average exercise price	$ 30.31
Number of shares exercisable (in Shares)	31,130
Options exercisable weighted average exercise price	$ 30.31
Range 05 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 40.57
Range of Exercise Prices - Upper limit	$ 40.57
Number of shares outstanding (in Shares)	48,690
Options outstanding weighted average remaining contractual life (Years)	9 years 9 months
Options outstanding weighted average exercise price	$ 40.57
Range 06 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 44.40
Range of Exercise Prices - Upper limit	$ 44.40
Number of shares outstanding (in Shares)	65,005
Options outstanding weighted average remaining contractual life (Years)	9 years 357 days
Options outstanding weighted average exercise price	$ 44.40

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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