Note 7 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Employee Stock Option [Member]
Stock Issued During Period, Shares, Share-based Compensation, Gross	74,000
Restricted Stock [Member] | Certain Officers and Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 1.7
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period	3 years
Restricted Stock Units (RSUs) [Member]
Stock Issued During Period, Shares, Share-based Compensation, Gross	98,000
Certain Officers and Employees [Member]
Stock Issued During Period, Shares, Restricted Stock Award, Gross	67,000
Treasury Stock, Shares, Acquired	310,000
Treasury Stock Acquired, Average Cost Per Share	$ 25.85
Treasury Stock, Value, Acquired, Par Value Method	$ 8.0
Treasury Stock, Shares	2,015,000	1,705,000
Treasury Stock, Average Value per Share	$ 18.74
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 35.9