Stockholders' Equity - Schedule of Share Repurchase Authorized by Board of Directors (Detail)	9 Months Ended
	Sep. 30, 2019 USD ($)
Equity, Class of Treasury Stock [Line Items]
Expiration	Dec. 31, 2020
October, 2017 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 200,000,000
Expiration	Dec. 31, 2019
April, 2018 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 300,000,000
Expiration	Dec. 31, 2020
October, 2018 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 300,000,000
Expiration	Dec. 31, 2020
February, 2019 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 300,000,000
Expiration	Dec. 31, 2020