Note 11 - Stock Based Compensation (Detail) (USD $)	12 Months Ended					12 Months Ended	3 Months Ended					3 Months Ended	9 Months Ended	12 Months Ended							12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Stock Options [Member] 2003 Plan [Member] Maximum [Member]	Dec. 31, 2003 Stock Options [Member] 2003 Plan [Member] Maximum [Member]	Dec. 31, 2012 Restricted Stock [Member] 2003 Plan [Member] Maximum [Member]	Mar. 31, 2012 Restricted Stock Units (RSUs) [Member] Initial [Member]	Jun. 30, 2012 Restricted Stock Units (RSUs) [Member] Common Class A [Member]	Mar. 31, 2012 Restricted Stock Units (RSUs) [Member] Executives and Other Key Employees [Member]	Mar. 31, 2012 Restricted Stock Units (RSUs) [Member] Maximum [Member]	Mar. 31, 2012 Restricted Stock Units (RSUs) [Member] Minimum [Member]	Mar. 31, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Net of Discount [Member] 2009 ESPP [Member]	Dec. 31, 2012 Per Share Discount [Member] 2009 ESPP [Member]	Dec. 31, 2012 Per Share Discount [Member]	Dec. 31, 2011 Per Share Discount [Member]	Dec. 31, 2010 Per Share Discount [Member]	Dec. 31, 2012 Common Class A [Member] 2003 Plan [Member]	Dec. 31, 2012 2003 Plan [Member]	Dec. 31, 2012 2009 ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																					2,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				5 years		5 years						4 years
Share-based Compensation Arrangement, Expiration Term				6 years	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant																				667,859		681,293
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in Dollars)																					$ 5,100,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition																					2 years
Deferred Compensation Arrangement with Individual, Shares Issued																						143,071
Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased (in Dollars per share)															$ 24.28	$ 4.29	$ 4.29	$ 2.56	$ 1.11
Stock Issued During Period, Shares, Restricted Stock Award, Gross								12,870	89,000			168,000
Attainment Level							133.00%			150.00%	75.00%	150.00%
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures												133,500
Share-based Compensation (in Dollars)	3,116,000	2,001,000	2,419,000				4,200,000						400,000	4,600,000
Allocated Share-based Compensation Expense (in Dollars)	$ 3,100,000	$ 2,300,000	$ 1,800,000										$ 300,000	$ 1,000,000