Note 7 - Deferred Compensation and Long-term Incentive Plans (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Deferred Compensation Arrangement with Individual, Employer Contribution	$ 2.0
Guaranteed Return				5.25%
Deferred Compensation Arrangement with Individual, Compensation Expense		0.3	0.3
Deferred Compensation Liability, Classified, Noncurrent	$ 4.4	$ 4.4			$ 3.6
Minimum [Member]
Deferred Compensation Arrangement with Individual, Requisite Service Period	1 year	1 year
Maximum [Member]
Deferred Compensation Arrangement with Individual, Requisite Service Period	7 years	7 years