Supplemental Cash Flow Information - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net cash provided from operating activities included:
Income taxes refunded from taxing authorities	$ 0	$ 73
Interest paid	(43,864)	(37,117)
Non-cash investing and financing activities included:
Increase in asset retirement costs capitalized	1,715	1,015
Increase in accrued capital expenditures	$ 39,569	$ 9,719