Note 5 - Stockholders' Equity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		4 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Apr. 23, 2013
Stock Repurchased During Period, Shares (in Shares)	284,283	0
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)	$ 78.15
Payments for Repurchase of Common Stock	$ 23,180	$ 441
Stock Repurchase Program, Remaining Authorized Repurchase Amount	18,735		100,000
Open Market Purchases [Member]
Payments for Repurchase of Common Stock	$ 22,218