Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		6 Months Ended
	Jul. 27, 2016	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule Of Stockholders Equity [Line Items]
Shares repurchased, value						$ 194,729	$ 117,733
Preferred stock, shares authorized		15,000,000	15,000,000	15,000,000		15,000,000
Preferred stock, par value		$ 0.01	$ 0.01	$ 0.01		$ 0.01
Dividend declared per share of common stock				$ 0.38	$ 0.35	$ 1.93	$ 1.65
January, 2016 [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase remaining authorization		$ 224,614		$ 224,614		$ 224,614
Share repurchase authorization expiration date						Dec. 31, 2017
Class A Common Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Conversion of Series A preferred stock into Class A common stock (in shares)		0	0
Class A Common Stock [Member] | Subsequent Event [Member]
Schedule Of Stockholders Equity [Line Items]
Dividend declared per share of common stock	$ 0.38
Dividend payable date	Aug. 19, 2016
Dividend date of record	Aug. 08, 2016
Dividend declare date	Jul. 27, 2016
Class A Common Stock [Member] | Executive Officers [Member]
Schedule Of Stockholders Equity [Line Items]
Shares repurchased, value						$ 4,900	$ 17,700
Series A Preferred Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares outstanding		7,921	7,921	7,921		7,921
Series B Preferred Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares outstanding		0	0	0		0