Note 7 - Leases - Lease Cost (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Operating lease cost, excluding short-term leases		$ 3,060	$ 2,902
Short-term lease cost (1)	[1]	1,633	22,152
Total lease cost		$ 4,693	$ 25,054

[1] Short-term lease costs are reported at gross amounts and primarily represent costs incurred for drilling rigs, most of which are short-term contracts not recognized as a right-of-use asset and lease liability on the balance sheet. The majority of such costs were recorded within Oil and natural gas properties, net, on the Consolidated Balance Sheet.