Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 138,346	$ 156,358
Cash paid for income taxes	2	0
Cash received for income tax refunds	148	20
Noncash Investing and Financing Items [Abstract]
Accrued capital expenditures	331,700		$ 223,600
Increase (Decrease) in Asset Retirement Obligations	$ 3,771	$ 1,042