Note 7 - Long-Term Debt (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	May 16, 2014	Dec. 31, 2013
Note 7 - Long-Term Debt (Details) [Line Items]
Credit Facility Syndication Number Of Commercial Banks		11
Line of Credit Facility, Maximum Borrowing Capacity		$ 500,000,000
Line Of Credit Facility, Maximum Borrowing Capacity Without Borrowing Base Requirement	400,000,000	400,000,000
Line of Credit Facility, Accordion Feature, Additional Revolving Credit Commitments Under Existing Loan Facility		100,000,000
Debt Issuance Cost	900,000
Long-term Debt, Excluding Current Maturities	115,216,000		40,000,000
Letters of Credit Outstanding, Amount	1,800,000
Line of Credit Facility, Remaining Borrowing Capacity	283,000,000
Line of Credit Facility, Current Borrowing Capacity	264,500,000
Previous Agreement [Member]
Note 7 - Long-Term Debt (Details) [Line Items]
Line of Credit Facility, Expiration Date	Mar. 14, 2017
Amended Agreement [Member]
Note 7 - Long-Term Debt (Details) [Line Items]
Line of Credit Facility, Expiration Date	May 16, 2019
Letter of Credit [Member]
Note 7 - Long-Term Debt (Details) [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 30,000,000
Minimum [Member]
Note 7 - Long-Term Debt (Details) [Line Items]
Line Of Credit Facility, Fixed Charge Coverage Ratio, Covenant	1.25
Line of Credit Facility, Interest Rate During Period	1.40%
Maximum [Member]
Note 7 - Long-Term Debt (Details) [Line Items]
Line Of Credit Facility, Leverage Ratio Covenant	3.75
Line of Credit Facility, Interest Rate During Period	3.25%