Note 14 - Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance as of December 31, 2017
Assets:
NYMEX fixed price derivative contracts	$	-	$	-	$	-	$	-
Total Assets	$	-	$	-	$	-	$	-
Liabilities:
NYMEX fixed price derivative contracts	$	-	$	13,208	$	-	$	13,208
NYMEX basis differential swap		-		-		16		16
Total Liabilities	$	-	$	13,208	$	16	$	13,224
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance as of December 31, 2018
Assets:
NYMEX fixed price derivative contracts	$	-	$	18,172	$	-	$	18,172
NYMEX basis differential swap		-		-		1,957		1,957
Total Assets	$	-	$	18,172	$	1,957	$	20,129
Liabilities:
NYMEX fixed price derivative contracts	$	-	$	-	$	-	$	-
NYMEX basis differential swap		-		-		5,050		5,050
Total Liabilities	$	-	$	-	$	5,050	$	5,050

Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

	(In thousands)
Unobservable inputs at January 1, 2018	$	(16	)
Changes in market value	$	(3,093	)
Settlements during the period	$	16
Unobservable inputs at December 31, 2018	$	(3,093	)