Supplemental Cash Flow Information (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Elements [Abstract]
Payments of interest and commitment fees	$ 86,800	$ 74,800	$ 49,700
Capitalized interest	17,100	13,800	13,300
Cash paid for income taxes	900	(800)	600
Incurred liabilities for fixed and intangible asset additions	68,600	61,200	52,500
Other Asset Additions Incurred but Not yet Paid	300	9,400
Gain on basis step up on historical interest	$ 332,380	$ 0	$ 0