Commitments and Contingencies (Balance Sheet Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Commitments and Contingencies [Abstract]
Operating lease right-of-use asset in other non-current assets	$ 2,640	$ 2,798
Operating lease liability in accrued liabilities	872	850
Operating lease liability in other liabilities	2,625	2,850
Total operating lease liabilities	$ 3,497	$ 3,700