Nature of Ops and Sign. Acctg Policies (Cash, Cash Equivalents, and Restricted Cash) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Sep. 18, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 3,671	$ 518	$ 45,585
Restricted cash, current	0	1,000
Restricted cash, long-term	46,673	40,730
Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows	$ 50,344	$ 42,248	$ 95,114	$ 33,045	$ 54,949