Deferred Charges, Goodwill And Other Assets, Net (Narrative) (Details) - USD ($) |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Credit Risk Contract [Member] | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Net liability | $ 0 | |
| Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Derivative notional amount | 675,000,000 | |
| Ineffective gain (loss) in interest expense | 74,000 | $ 43,000 |
| Estimated additional amount to be reclassified to interest expense | $ 4,000,000 | |