Deferred Charges, Goodwill And Other Assets, Net (Narrative) (Details) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
| Credit Risk Contract [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Net liability | $ 0 | $ 0 | ||
| Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative notional amount | 675,000,000 | 675,000,000 | ||
| Ineffective gain (loss) in interest expense | $ (100,000) | $ 11,000 | (174,000) | $ (32,000) |
| Estimated additional amount to be reclassified to interest expense | $ 5,700,000 | |||