Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		2 Months Ended	3 Months Ended									12 Months Ended
	Feb. 01, 2017	Feb. 17, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Quarterly dividend declared			$ 0.28	$ 0.28	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.18	$ 0.18	$ 0.18	$ 1.00	$ 0.80	$ 0.18
Total Number of Shares Repurchased												10,303,047	11,856,169	6,856,866
Value of shares repurchased												$ 774,565	$ 700,715	$ 409,651
Subsequent Events [Member]
Subsequent Event [Line Items]
Quarterly dividend declared	$ 0.28
Quarterly dividend declared date	Feb. 01, 2017
Quarterly dividend payable date	Mar. 15, 2017
Quarterly dividend record date	Feb. 17, 2017
Total Number of Shares Repurchased		1,000,000
Average Price Paid Per Share		$ 80.70
Value of shares repurchased		$ 77,500