Commitments and Contingencies (Balance Sheet Information) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	May 31, 2021	Dec. 31, 2020
Commitments and Contingencies [Abstract]
Operating lease right-of-use asset in other non-current assets	$ 5,569	$ 3,398	$ 2,798
Operating lease liability in accrued liabilities	1,003		850
Operating lease liability in other liabilities	6,574		2,850
Total operating lease liabilities	$ 7,577	$ 3,398	$ 3,700