Note 6 - Stockholders' Equity and Equity Compensation (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended				3 Months Ended				3 Months Ended	12 Months Ended	3 Months Ended
	Dec. 31, 2013	Mar. 31, 2013	Mar. 31, 2013 Employee Plan [Member]	Mar. 31, 2013 Director Plan [Member]	Mar. 31, 2013 Restricted Stock [Member]	Mar. 31, 2012 Restricted Stock [Member]	Mar. 31, 2013 Stock Options [Member]	Mar. 31, 2012 Stock Options [Member]	Mar. 31, 2013 In Connection with Equity Compensation Programs [Member]	Dec. 31, 2013 In Connection with Equity Compensation Programs [Member]	Mar. 31, 2013 Through the Open Market Repurchase Program [Member]	Mar. 31, 2013 Minimum [Member]	Mar. 31, 2013 Maximum [Member]
Stock Repurchase Program, Authorized Amount	$ 5.0									$ 5.0
Stock Repurchased During Period, Shares (in Shares)									48,975		151,063
Stock Repurchased During Period, Value									1.1		3.4
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)									$ 23.38		$ 22.82
Number of Equity-Based Compensation Plans		2
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)			2,500,000	250,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in Shares)			322,910	208,266
Allocated Share-based Compensation Expense					1.2	1.0	0.6
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized					$ 17.0		$ 2.2
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition					3 years 255 days		1 year 292 days
Deferred Stock Unit, Share Transfer Obligation (in Shares)		1
Stock Options, General Term												7 years	10 years
Price Per Share For Intrinsic Value Calculation Stock Options (in Dollars per share)							$ 23.15	$ 17.83