Note 4 - Stock Benefit Plans (Detail) - Options Outstanding and Exercisable: (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2010
Options Outstanding, Number Outstanding (in Shares)	65	94	80	488
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 277 days
Options Outstanding, Weighted Average Exercise Price	$ 30.93	$ 31.89	$ 35.61	$ 40.50
Options Exercisable, Number Exercisable (in Shares)	46	68	69
Options Exercisable, Weighted Average Exercise Price	$ 31.98	$ 33.12	$ 36.60
$25.00 - $30.00 [Member]
Exercise Price, Lower Limit	$ 25.00
Exercise Price, Upper Limit	$ 30.00
Options Outstanding, Number Outstanding (in Shares)	45
Options Outstanding, Weighted Average Remaining Contractual Life	8 years 204 days
Options Outstanding, Weighted Average Exercise Price	$ 28.67
Options Exercisable, Number Exercisable (in Shares)	26
Options Exercisable, Weighted Average Exercise Price	$ 28.88
$30.01 - $35.00 [Member]
Exercise Price, Lower Limit	$ 30.01
Exercise Price, Upper Limit	$ 35.00
Options Outstanding, Number Outstanding (in Shares)	15
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 153 days
Options Outstanding, Weighted Average Exercise Price	$ 32.84
Options Exercisable, Number Exercisable (in Shares)	12
Options Exercisable, Weighted Average Exercise Price	$ 32.84
$35.01 - $40.00 [Member]
Exercise Price, Lower Limit	$ 35.01
Exercise Price, Upper Limit	$ 40.00
$40.01 - $45.00 [Member]
Exercise Price, Lower Limit	$ 40.01
Exercise Price, Upper Limit	$ 45.00
Options Outstanding, Number Outstanding (in Shares)	5
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 69 days
Options Outstanding, Weighted Average Exercise Price	$ 40.72
Options Exercisable, Number Exercisable (in Shares)	8
Options Exercisable, Weighted Average Exercise Price	$ 40.72