Note 16 - Supplemental Cash Flow Information - Summary of Supplemental Non-cash Transaction and Nonmonetary Exchange Information (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Capital expenditures incurred but not paid at September 30	$ 6,411	$ 5,823
Dividends payable at September 30, 2020	16	0
Additions to ARO asset	137	58
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$ 10,210	$ 592

Amount of asset retirement obligations incurred during the period.

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