Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Provision of Income Taxes [Line Items]
Current	$ (45,700)	$ 2,400	$ 77,700
Deferred	30,700	(66,200)	109,400
Income taxes	(15,062)	(63,802)	187,141
Federal
Reconciliation of Provision of Income Taxes [Line Items]
Current	(83,300)	(41,300)	49,400
Deferred	29,900	(66,600)	109,600
Income taxes	(53,400)	(107,900)	159,000
State
Reconciliation of Provision of Income Taxes [Line Items]
Current	5,600	2,700	4,900
Deferred	900	600	300
Income taxes	6,500	3,300	5,200
Foreign
Reconciliation of Provision of Income Taxes [Line Items]
Current	32,000	41,000	23,400
Deferred	(100)	(200)	(500)
Income taxes	$ 31,900	$ 40,800	$ 22,900