Stock-based Compensation and Other Employee Benefits - Schedule of Performance-Based and Market-Based RSUs and Stock Options (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Options granted (in shares)	0
RSUs
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	1,209,000	1,265,000	920,000
RSUs, Granted (in shares)	925,000	675,000	821,000
RSUs, Vested (in shares)	(20,000)	(284,000)	(226,000)
RSUs, Forfeited (in shares)	(648,000)	(447,000)	(250,000)
Non-vested, ending balance (in shares)	1,466,000	1,209,000	1,265,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	0	0	16,000
Options granted (in shares)	0	0	0
Options, vested (in shares)	0	0	(4,000)
Options, forfeited (in shares)	0	0	(12,000)
Non-vested, ending balance (in shares)	0	0	0
Non-vested performance-based RSUs	21.00%
Market-based
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	23,000	23,000	23,000
RSUs, Granted (in shares)	47,000	0	0
RSUs, Vested (in shares)	0	0	0
RSUs, Forfeited (in shares)	0	0	0
Non-vested, ending balance (in shares)	70,000	23,000	23,000