Note 12 - Stock-Based Compensation (Detail) - Options Outstanding (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Options Outstanding (in Shares)	1,156,242	1,134,602	1,482,077
Weighted Average Exercise Price	$ 46.80	$ 46.75	$ 46.92
Weighted Average Remaining Contractual Life in Years	2 years 255 days
Exercise Price Range 1 [Member]
Options Outstanding (in Shares)	28,800
Exercise Prices	$ 37.70
Weighted Average Exercise Price	$ 37.70
Weighted Average Remaining Contractual Life in Years	1 year 36 days
Exercise Price Range 2 [Member] | Minimum [Member]
Exercise Prices, Low range	$ 45.80
Exercise Price Range 2 [Member] | Maximum [Member]
Exercise Prices, Upper range	$ 46.69
Exercise Price Range 2 [Member]
Options Outstanding (in Shares)	1,015,802
Weighted Average Exercise Price	$ 46.58
Weighted Average Remaining Contractual Life in Years	3 years
Exercise Price Range 3 [Member] | Minimum [Member]
Exercise Prices, Low range	$ 49.50
Exercise Price Range 3 [Member] | Maximum [Member]
Exercise Prices, Upper range	$ 51.50
Exercise Price Range 3 [Member]
Options Outstanding (in Shares)	111,640
Weighted Average Exercise Price	$ 51.11
Weighted Average Remaining Contractual Life in Years	73 days