Supplemental Cash Flow Information - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended			12 Months Ended
	Jun. 30, 2021		Jun. 30, 2020	Dec. 31, 2020	[1]
Net cash provided from operating activities included:
Income taxes refunded from taxing authorities	$ 0		$ 2,154
Interest paid	(87,337)		(78,265)
Non-cash investing and financing activities included:
Increase in asset retirement costs capitalized	2,098	[1]	4,247	$ 2,610
Increase (decrease) in accrued capital expenditures	$ 3,185		$ (31,307)

[1] Includes costs incurred whether capitalized or expensed.