Stock Repurchase Program - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Dec. 20, 2019	Jan. 31, 2018	Dec. 31, 2019	Oct. 31, 2019	Jun. 14, 2019
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount				$ 500,000,000.0	$ 500,000,000.0
Remaining amount available for further repurchases				$ 400,000,000
Accelerated Share Repurchase Program September 2017
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, prepayment during period, derivative settlement		$ 20,000,000.0
Subsequent Event | Accelerated Share Repurchase Program December 2019
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount			$ 100,000,000.0
Prepayment during period	$ 100,000,000.0
Initial share delivery, amount			$ 80,000,000.0
Prepayment during prior period, derivative settlement	$ 20,000,000.0