Note 6 - Stockholders' Equity and Equity Compensation (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended			12 Months Ended	9 Months Ended			9 Months Ended			3 Months Ended		9 Months Ended
	Feb. 28, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2014 Through the Open Market Repurchase Program [Member]	Sep. 30, 2014 In Connection with Equity Compensation Programs [Member]	Dec. 31, 2014 In Connection with Equity Compensation Programs [Member]	Sep. 30, 2014 Employee Stock Option [Member]	Sep. 30, 2014 Stock Awards [Member]	Dec. 31, 2013 Stock Awards [Member]	Sep. 30, 2014 Deferred Stock Units [Member]	Sep. 30, 2013 Deferred Stock Units [Member]	Dec. 31, 2013 Deferred Stock Units [Member]	Sep. 30, 2014 Employee Stock Option [Member]	Sep. 30, 2013 Employee Stock Option [Member]	Sep. 30, 2014 Employee Stock Option [Member]	Sep. 30, 2013 Employee Stock Option [Member]	Sep. 30, 2014 2013 Employee Plan [Member]	Sep. 30, 2014 2013 Employee Plan [Member] Stock Awards [Member]	Sep. 30, 2014 2011 Director Plan [Member]	Sep. 30, 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)					860,761	53,286		419,643
Stock Repurchased During Period, Value					20,000,000	1,200,000		9,900,000
Stock Repurchased During Period, Net Cash Value								1,400,000
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)					$ 23.24	$ 22.66
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									707,487	555,025	215,565		214,455						1,953,034		135,396
Allocated Share-based Compensation Expense		1,000,000	800,000	2,800,000							788,000	890,000		100,000	400,000	600,000	1,400,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized		$ 11,400,000		$ 11,400,000										$ 200,000		$ 200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition				2 years 0 months 22 days												0 years 10 months 24 days
Price Per Share For Intrinsic Value Calculation Stock Options (in Dollars per share)		$ 22.25	$ 23.72	$ 22.25