Share-Based Compensation - Summary of Number of Awards Granted and Grand Date Fair Value (Detail) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets Valuation Allowance [Line Items]
Grant date fair value	$ 24.47
TSR Awards
Deferred Tax Assets Valuation Allowance [Line Items]
Number of shares (in shares)	55	46	101
Grant date fair value	$ 24.65	$ 29.84	$ 9.38
ROIC Awards
Deferred Tax Assets Valuation Allowance [Line Items]
Number of shares (in shares)	55	53	101
Grant date fair value	$ 24.55	$ 24.20	$ 11.31