Statements of Condensed Consolidated Comprehensive (Loss) Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net (loss) income		$ (263,075)	$ 125,566	$ (430,214)	$ 316,257
Other comprehensive income (loss), net of tax:
Net change in interest rate cash flow hedges	[1]	0	42	0	84
Other post-retirement benefits liability adjustment	[2]	72	76	84	152
Other comprehensive income (loss)		72	118	84	(260)
Comprehensive (loss) income		(263,003)	125,684	(430,130)	315,997
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 $20 for the three and six months ended June 30, 2019.

[2] Net of tax expense of $24 and $26 for the three months ended June 30, 2020 and 2019, respectively, and $48 and $52 for the six months ended June 30, 2020 and 2019, respectively.

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