Note 6 - Stockholders' Equity and Equity Compensation (Details) (USD $)	1 Months Ended	3 Months Ended				12 Months Ended			3 Months Ended			3 Months Ended
	Feb. 28, 2014	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Through the Open Market Repurchase Program [Member]	Mar. 31, 2014 In Connection with Equity Compensation Programs [Member]	Dec. 31, 2014 In Connection with Equity Compensation Programs [Member]	Mar. 31, 2014 Stock Awards [Member]	Dec. 31, 2013 Stock Awards [Member]	Mar. 31, 2014 Deferred Stock Units [Member]	Mar. 31, 2013 Deferred Stock Units [Member]	Dec. 31, 2013 Deferred Stock Units [Member]	Mar. 31, 2014 Employee Stock Option [Member]	Mar. 31, 2013 Employee Stock Option [Member]	Mar. 31, 2014 2013 Employee Plan [Member]	Mar. 31, 2014 2013 Employee Plan [Member] Stock Awards [Member]	Mar. 31, 2014 2011 Director Plan [Member]	Mar. 31, 2014 Deferred Compensation, Share-based Payments [Member] 2011 Director Plan [Member]
Note 6 - Stockholders' Equity and Equity Compensation (Details) [Line Items]
Stock Repurchase Program, Authorized Amount	$ 20,000,000					$ 10,000,000
Stock Repurchased During Period, Shares (in Shares)				142,700	96,375
Stock Repurchased During Period, Value				3,400,000	2,100,000
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)				$ 23.70	$ 21.71
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)														2,895,000		250,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number							861,364	555,025	210,284		214,455				2,069,721		168,300
Allocated Share-based Compensation Expense		900,000	1,200,000						0	0		400,000	600,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized		$ 17,100,000										$ 1,300,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		2 years 6 months										1 year 10 months
Price Per Share For Intrinsic Value Calculation Stock Options (in Dollars per share)		$ 25.31	$ 23.15