Supplemental Oil and Gas Disclosures (Unaudited) (Future Net Cash Flows From Proved Oil and Gas Reserves) (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Gross Amounts
Future cash inflows	$ 71,400
Future production costs	14,664
Future net cash flows before income tax expense	56,736
10% discount to reflect timing of cash flows	(19,897)
Standardized measure of discounted cash flows	36,839
Net Amounts
Future net cash flows before income tax expense	44,821
10% discount to reflect timing of cash flows	(15,719)
Standardized measure of discounted cash flows	$ 29,102