Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2020

Asset Retirement Obligation [Abstract]

Reconciliation of the company's asset retirement obligation

A reconciliation of the Company's liability, which the current portion is included in other accrued liabilities on the Consolidated Balance Sheets, for the years ended December 31 was as follows:

	2020		2019
	(In thousands)
Balance at beginning of year	$	417,575	$	375,553
Liabilities incurred	11,560		25,869
Liabilities acquired	1,378		486
Liabilities settled	(5,369)		(7,097)
Accretion expense*	21,668		19,789
Revisions in estimates	107		2,975
Balance at end of year	$	446,919	$	417,575

*    Includes $20.1 million and $18.3 million in 2020 and 2019, respectively, related to regulatory assets.