Note 4 - Long-Term Debt (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Debt Disclosure [Abstract]
Line of Credit Facility, Expiration Date	May 31, 2016
Line of Credit Facility, Current Borrowing Capacity	$ 50
Line of Credit Facility, Maximum Borrowing Capacity	75
Line of Credit Facility, Amount Outstanding	7.4
Letters of Credit Outstanding, Amount	8.3
Line of Credit Facility, Remaining Borrowing Capacity	$ 34.3
Debt, Weighted Average Interest Rate	1.05%