Note 12 - Employee Benefit Plans (Detail) - Summary of information about stock options under the plans: (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
$23.78 - $23.78 [Member]
Range of Exercise Prices - Lower limit	$ 23.78
Range of Exercise Prices - Upper limit	$ 23.78
Options Outstanding, Number of Shares (in Shares)	46
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	1 year 164 days
Options Outstanding, Weighted Average Exercise Price	$ 23.78
Options Exercisable, Number of Shares (in Shares)	46
Options Exercisable, Weighted Average Exercise Price	$ 23.78
$24.50 - $24.50 [Member]
Range of Exercise Prices - Lower limit	$ 24.50
Range of Exercise Prices - Upper limit	$ 24.50
Options Outstanding, Number of Shares (in Shares)	31
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 142 days
Options Outstanding, Weighted Average Exercise Price	$ 24.50
Options Exercisable, Number of Shares (in Shares)	31
Options Exercisable, Weighted Average Exercise Price	$ 24.50
$26.19 - $27.67 [Member]
Range of Exercise Prices - Lower limit	$ 26.19
Range of Exercise Prices - Upper limit	$ 27.67
Options Outstanding, Number of Shares (in Shares)	50
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3 years 94 days
Options Outstanding, Weighted Average Exercise Price	$ 26.20
Options Exercisable, Number of Shares (in Shares)	50
Options Exercisable, Weighted Average Exercise Price	$ 26.20
$28.42 - $28.42 [Member]
Range of Exercise Prices - Lower limit	$ 28.42
Range of Exercise Prices - Upper limit	$ 28.42
Options Outstanding, Number of Shares (in Shares)	46
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 years 105 days
Options Outstanding, Weighted Average Exercise Price	$ 28.42
Options Exercisable, Number of Shares (in Shares)	46
Options Exercisable, Weighted Average Exercise Price	$ 28.42
$30.31 - $30.31 [Member]
Range of Exercise Prices - Lower limit	$ 30.31
Range of Exercise Prices - Upper limit	$ 30.31
Options Outstanding, Number of Shares (in Shares)	45
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	5 years 76 days
Options Outstanding, Weighted Average Exercise Price	$ 30.31
Options Exercisable, Number of Shares (in Shares)	36
Options Exercisable, Weighted Average Exercise Price	$ 30.31