Note 2 - Derivative Instruments and Hedging Activities (Details) - Outstanding Commodity Forward Contracts (USD $) In Thousands, unless otherwise specified	6 Months Ended			12 Months Ended	6 Months Ended
	Jun. 30, 2014 Commodity Forward Contract Two [Member]	Jun. 30, 2014 Commodity Forward Contract Three [Member]	Jun. 30, 2013 Commodity Forward Contract One [Member]	Dec. 31, 2013 Commodity Forward Contract One [Member]	Jun. 30, 2013 Commodity Forward Contract Four [Member]	Jun. 30, 2013 Commodity Forward Contract Five [Member]	Jun. 30, 2013 Commodity Forward Contract Six [Member]	Jun. 30, 2013 Commodity Forward Contract Seven [Member]
Note 2 - Derivative Instruments and Hedging Activities (Details) - Outstanding Commodity Forward Contracts [Line Items]
Trade date	Jan. 31, 2014	Mar. 11, 2014	Jun. 21, 2013	Jun. 21, 2013	Oct. 29, 2012	Feb. 26, 2013	Mar. 01, 2013	Apr. 15, 2013
Effective date	Feb. 01, 2014	Apr. 01, 2014	Oct. 01, 2013	Oct. 01, 2013	Jan. 01, 2013	Mar. 01, 2013	Mar. 01, 2013	May 01, 2013
Notional amount	$ 3,879	$ 3,014	$ 2,169	$ 2,169	$ 3,472	$ 2,677	$ 2,636	$ 4,033
Termination date	Dec. 31, 2014	Dec. 31, 2014	Jun. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013