Statements of Condensed Consolidated Comprehensive (Loss) Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net loss		$ (600,640)	$ (361,028)	$ (1,030,854)	$ (44,771)
Other comprehensive income (loss), net of tax:
Net change in interest rate cash flow hedges	[1]	0	43	0	127
Other post-retirement benefits liability adjustment	[2]	72	77	156	229
Other comprehensive income (loss)		72	120	156	(140)
Comprehensive loss		(600,568)	(360,908)	(1,030,698)	(44,911)
Change in accounting principle
Other comprehensive income (loss), net of tax:
Other comprehensive income (loss)	[3]	$ 0	$ 0	$ 0	$ (496)

[1] Net of tax expense of $10 and $30 for the three and nine months ended September 30, 2019.

[2] Net of tax expense of $23 and $26 for the three months ended September 30, 2020 and 2019, respectively, and $71 and $78 for the nine months ended September 30, 2020 and 2019, respectively.

[3] Related to adoption of Accounting Standards Update (ASU) 2018-02.