| Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands | 6 Months Ended | |
|---|---|---|
| Jun. 30, 2016 | Jun. 30, 2015 | |
| Supplemental Cash Flow Information [Abstract] | ||
| Cash paid during the period for interest, net of amounts capitalized | $ 59,260 | $ 46,165 | 
| Balance in property, plant and equipment, net funded with accounts payable and accrued liabilities | $ 472,400 | $ 383,700 | 
| X | ||||||||||
| 
- Definition Future cash outflow to pay for construction in progress expenditures that have occurred. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Definition The amount of cash paid for interest during the period net of cash paid for interest that is capitalized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- References No definition available. 
 |