Reclassifications from Accumulated Other Comprehensive Income (Loss) to Consolidated Statement of Income (Detail) - USD ($) $ in Thousands	4 Months Ended	5 Months Ended	12 Months Ended
	Jul. 31, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income and other, net	$ 2,384	$ 2,771	$ 6,598	$ 11,294
Interest and other debt costs, net	(11,179)	(13,009)	(29,068)	(30,439)
Loss before income taxes	(1,648,143)	(36,687)	$ (113,495)	(153,519)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Loss before income taxes	106	169		(1,132)
Reclassification out of Accumulated Other Comprehensive Income | Realized Gains on Available for Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other debt costs, net	$ 106	$ 169		404
Reclassification out of Accumulated Other Comprehensive Income | Retiree Medical Plan
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income and other, net				$ (1,536)