Commitments and Contingencies (Letter of Credit) (Narrative) (Details) - Letter of Credit [Member] - Bank of America Syndicate [Member] $ in Millions	Sep. 30, 2020 USD ($)
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 6.3
Performance Guarantee [Member]
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 5.7