Financial Instruments and Risk Management (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)
Derivatives [Line Items]
Deferred net gains on derivatives accumulated in other comprehensive income expected to be reclassified to net income in next twelve months	$ 9,900,000
Maximum
Derivatives [Line Items]
Remaining maturity of derivative contracts	4 years
Aggregate unrealized gain of derivative contracts with single counterparty	$ 5,100,000