Quarterly report pursuant to Section 13 or 15(d)

Organization and Accounting Policies (Reconciliation of Cash, Cash Equivalents, and Restricted Cash) (Details)

v3.21.1
Organization and Accounting Policies (Reconciliation of Cash, Cash Equivalents, and Restricted Cash) (Details) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Mar. 31, 2020
Dec. 31, 2019
Organization and Accounting Policies [Abstract]        
Cash and cash equivalents $ 19,251 $ 47,853 $ 60,973  
Restricted cash - current 82 86 994  
Restricted cash - non-current 1,752 925 925  
Abandonment funding 22,862 12,453 11,227  
Total cash, cash equivalents and restricted cash $ 43,947 $ 61,317 $ 74,119 $ 59,124