CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	4 Months Ended	5 Months Ended	12 Months Ended
	Jul. 31, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (1,646,909)	$ (38,726)	$ (141,219)	$ (171,771)
Other comprehensive income (loss):
Unrealized gains (losses) on available for sale securities, net of tax of $0, $0, $0, and $0, respectively	163	256		(256)
Change in supplemental executive retirement plan pension liability, net of tax of $0, $0, $0 and $0, respectively	(536)	(1,582)	(2,121)	2,214
Change in pension plan minimum liability, net of tax of $0, $0, $0, and $0, respectively	(594)	(357)	(309)	1,919
Change in other benefit plan minimum liability, net of tax of $0, $0, $0 and $0, respectively	(1,468)	1,536		(1,536)
Total comprehensive loss	$ (1,649,344)	$ (38,873)	$ (143,649)	$ (169,430)