Disclosure Of Fair Value Of Financial Instruments (Details) - USD ($) |
Jun. 30, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Disclosure Of Fair Value Of Financial Instruments [Abstract] | ||
| Fair value of Company's long-term debt | $ 2,046,116,000 | $ 2,133,214,000 |
| Book value of Company's long-term debt | $ 2,034,819,000 | $ 2,088,654,000 |