Stockholders' Equity - Additional Information (Detail) - USD ($)		1 Months Ended	9 Months Ended
	Mar. 15, 2018	Feb. 28, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Nov. 30, 2015
Stockholders Equity Note [Line Items]
Remaining authorized repurchases under share repurchase program			$ 659,100,000
Par value of common stock			$ 1.00
Dividends paid	$ 154,000,000.0			$ 153,967,000
Dividend Declared [Member]
Stockholders Equity Note [Line Items]
Special dividend declared per share		$ 10.00
Dividend record date		Mar. 05, 2018
Dividend payable nature			special
2019 Repurchase Program
Stockholders Equity Note [Line Items]
Aggregate amount of common stock authorized for repurchase			$ 500,000,000.0
2015 Repurchase Program
Stockholders Equity Note [Line Items]
Aggregate amount of common stock authorized for repurchase						$ 400,000,000.0
2018 Repurchase Program
Stockholders Equity Note [Line Items]
Aggregate amount of common stock authorized for repurchase					$ 400,000,000.0