Supplemental Cash Flow Information - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net cash provided from operating activities included:
Income taxes paid to (refunded from) taxing authorities		$ 100	$ (156)	$ (347)
Interest paid		168,826	165,530	159,137
Non-cash investing and financing activities included:
Asset retirement costs capitalized, net	[1]	22,184	56,822	76,373
(Decrease) increase in accrued capital expenditures		$ (225,455)	$ 150,604	$ 27,079

[1] Includes cost incurred whether capitalized or expensed.