Stockholders' Equity - Additional Information (Detail) - USD ($)			3 Months Ended
	Apr. 25, 2018	Apr. 24, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule Of Stockholders Equity [Line Items]
Shares repurchased, value			$ 145,949,000	$ 106,048,000
Preferred stock, shares authorized			15,000,000		15,000,000
Preferred stock, par value			$ 0.01		$ 0.01
Dividend declared per share of common stock			$ 1.71	$ 1.58
Subsequent Event [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase remaining authorization	$ 351,000,000
Dividend declared per share of common stock		$ 0.44
Dividend payable date		May 18, 2018
Dividend date of record		May 07, 2018
Dividend declare date		Apr. 25, 2018
October, 2017 [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase remaining authorization			$ 102,435,000
Share repurchase authorization expiration date			Dec. 31, 2019
Share repurchase authorization			$ 200,000,000
April 25, 2018 [Member] | Subsequent Event [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase authorization expiration date	Dec. 31, 2020
Share repurchase authorization	$ 300,000,000
Class A Common Stock [Member] | Executive Officers [Member]
Schedule Of Stockholders Equity [Line Items]
Shares repurchased, value			$ 16,400,000	$ 14,700,000
Series A Preferred Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares outstanding			0		0
Series B Preferred Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares outstanding			0		0