Exit and Termination Costs - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended					9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost And Reserve [Line Items]
Restructuring Charges	$ 11,789		$ 521,633			$ 9,557	$ 533,525
Severance costs	0		4,191			509	5,638
Workforce Reduction
Restructuring Cost And Reserve [Line Items]
Severance costs			3,700
North Louisiana
Restructuring Cost And Reserve [Line Items]
Accretion expense						36,600
Exit cost						426,600
Restructuring Charges		$ 28,200
Severance costs			2,500
Pennsylvania
Restructuring Cost And Reserve [Line Items]
Exit cost	$ 186		$ 233	$ 10,400		580	$ 10,678
Pennsylvania | Capacity Releases on Transportation Pipelines
Restructuring Cost And Reserve [Line Items]
Exit cost						$ 7,900
Northwest Pennsylvania
Restructuring Cost And Reserve [Line Items]
Severance costs					$ 1,600