Note 8 - Stockholders' Equity (Detail) - Share Repurchases (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended						17 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2012
Total purchase price (in thousands) (in Dollars)	23,279		13,568		1,626
Average purchase price per share (in Dollars per share)	24.41		17.29		7.88
Common Class A [Member]
Shares repurchased (1)	848,092	[1]	716,431	[1]	100,893	[1]
Average purchase price per share (in Dollars per share)							$ 22.33
Share Repurchase Plan [Member]
Total purchase price (in thousands) (in Dollars)	20,698		12,389		795

[1] Includes only share repurchased under repurchase plans. An additional 80,687, 56,012 and 61,153 shares were repurchased in association with tax withholdings on the exercise of stock options in 2012, 2011 and 2010, respectively.