Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments And Risk Management (Narrative) (Details)

v3.8.0.1
Financial Instruments And Risk Management (Narrative) (Details)
3 Months Ended
Mar. 31, 2018
USD ($)
Derivative [Line Items]  
Deferred net gains on derivatives accumulated in other comprehensive income expected reclassification to net income in next twelve months $ 12,381,000
Maximum [Member]  
Derivative [Line Items]  
Derivatives maximum remaining maturity 3 years
Aggregate unrealized gain of derivative contracts with single counterparty $ 2,000,000