Note 6 - Senior Notes, Credit Facilities and Capital Leases (Details) (USD $)	12 Months Ended						1 Months Ended
	Dec. 31, 2013	Jan. 06, 2014	Oct. 28, 2013	Apr. 12, 2013	Dec. 31, 2012	Oct. 31, 2009	Feb. 28, 2014 Subsequent Event [Member]	Apr. 30, 2013 Original Amount [Member]	Apr. 30, 2013 Revised Amount [Member]
Note 6 - Senior Notes, Credit Facilities and Capital Leases (Details) [Line Items]
Debt Instrument, Face Amount				$ 500,000,000
Underwriting Discount on Senior Notes				2.00%
Debt Instrument, Unamortized Discount	9,300,000			10,000,000
Debt Instrument, Interest Rate, Stated Percentage	6.875%	6.875%
Interest Costs Capitalized	6,500,000
Interest Expense, Debt	19,100,000						100,000,000
Proceeds from Issuance of Senior Long-term Debt	490,000,000
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	100.00%
Percentage of Notes Redeemable	35.00%
Debt Instrument, Redemption Price, Percentage	101.00%
Percentage Of Notes Tendered For Exchange			99.99%
Line of Credit Facility, Maximum Borrowing Capacity	100,000,000					60,000,000
Line of Credit Facility, Commitment Fee Amount								150,000,000	100,000,000
Senior Leverage Ratio	2.50
Leverage Ratio	4.00
Interest Coverage Ratio	3.0
Capital Leases Including Purchase Option	22,800,000
Capital Lease Obligations, Current	8,471,000				5,564,000
Capital Lease Obligations, Noncurrent	14,332,000				11,935,000
Capital Lease Obligations	22,740,000				17,500,000
Capital Leases, Future Minimum Payments Due	23,833,000
Capital Leases, Future Minimum Payments, Interest Included in Payments	$ 1,093,000