Commitments and Contingencies (Letter of Credit) (Narrative) (Details) - Bank of America Syndicate [Member] - Letter of Credit [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 3.4	$ 6.2
Performance Guarantee [Member]
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 1.6