Note 3 - Long-Term Debt (Detail) (USD $)	1 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012
Line of Credit Facility, Amount Outstanding	$ 2,700,000	$ 2,700,000
Letters of Credit Outstanding, Amount	7,400,000	7,400,000
Line of Credit Facility, Remaining Borrowing Capacity	39,900,000	39,900,000
Line of Credit Facility, Dividend Restrictions, Percentage of Net Income Limit		25.00%
Dividend Payment Restrictions Schedule, Amounts Paid	0.75
Minimum [Member]
Line of Credit Facility, Maximum Borrowing Capacity	50,000,000	50,000,000
Maximum [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 75,000,000	$ 75,000,000
Credit Facility [Member]
Long-term Debt, Weighted Average Interest Rate	1.05%	1.05%