Preferred and Common Stock - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Oct. 31, 2018
Class of Stock [Line Items]
Preferred stock, authorized (in shares)		100,000,000
Preferred stock, par value (in dollars per share)		$ 0.01
Preferred stock, issued (in shares)		0	0
Common stock shares authorized		750,000,000
Common stock par value		$ 0.01
Common stock shares issued		185,978,069	185,580,166
Common stock shares outstanding		185,978,069	185,580,166
Common stock were reserved for future issuance		24,769,326
Common stock repurchase program, authorized amount					$ 200,000,000
Repurchase of common stock shares		0	0
Common stock dividends declared during period		$ 0	$ 0	$ 0
Stock based compensation expense		25,000,000	30,000,000	35,000,000
Stock-based compensation expense capitalized		$ 0	$ 0	$ 0
Fair value of stock options granted		$ 6.12	$ 10.86	$ 21.32
Volatility		41.12%
Average risk-free interest rate		1.83%
Dividend yield		0.00%
Annual pre- and post-vesting forfeitures		4.00%
Exercise behavior		61.00%
Life (years)		6 years
Number of options, Outstanding		2,036,625
Number of options, Outstanding weighted average remaining contractual life		5 years 6 months 10 days
Total intrinsic value of options outstanding		$ 5,000,000
Stock options vested and exercisable		1,416,986
Weighted average exercise price, vested and exercisable		$ 27.79
Cash received from option exercises		$ 1,000,000	$ 2,000,000	$ 23,000,000
Total intrinsic value of options exercised		$ 0	$ 1,000,000	$ 26,000,000
Number of options, Vested and expected to vest, weighted average remaining contractual life		4 years 3 months 21 days
Total intrinsic value of options vested and exercisable		$ 3,000,000
Unrecognized compensation costs on non-vested stock option grants (pretax)		$ 26,000,000
Unrecognized compensation costs on non-vested awards, weighted average period of recognition in years		1 year 7 months 13 days
Minimum [Member]
Class of Stock [Line Items]
Stock based compensation expense, stock units percentage		80.00%	80.00%	80.00%
Maximum [Member]
Class of Stock [Line Items]
Stock based compensation expense, stock units percentage		90.00%	90.00%	90.00%
Stock Units [Member]
Class of Stock [Line Items]
Stock granted, Fair value		$ 15.71
Number of shares withheld to meet statutory tax requirements		101,447
Stock Units [Member] | Cliff Vest [Member]
Class of Stock [Line Items]
Vesting rights percentage		0.3333%
Restricted Stock [Member]
Class of Stock [Line Items]
Volatility		41.65%
Average risk-free interest rate		1.38%
Stock granted, Fair value		$ 21.43	$ 35.70
Common Stock [Member]
Class of Stock [Line Items]
Shares issued for employee stock-based compensation plans		397,903	809,917	1,293,336
Repurchase of common stock shares	1,723,800
Repurchase of common stock value	$ 50,000,000
Stock Options [Member]
Class of Stock [Line Items]
Number of options, Outstanding		2,036,625	2,246,563
Stock Options [Member] | Grade Vest [Member]
Class of Stock [Line Items]
Vesting rights percentage		0.3333%
Common stock service period		3 years
Common stock contractual term		10 years