Supplemental Cash Flow Information - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net cash provided from operating activities included:
Income taxes refunded from taxing authorities		$ 343	$ 0	$ 7,521
Interest paid		(168,471)	(189,443)	(207,433)
Non-cash investing and financing activities included:
Asset retirement costs capitalized, net	[1]	2,610	11,193	28,826
Decrease in accrued capital expenditures		$ (23,625)	$ (20,104)	$ (119,021)

[1] Includes cost incurred whether capitalized or expensed.