Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands	Feb. 09, 2017	Mar. 09, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Stock repurchase program authorized to be repurchased			900,000	3,800,000
Shares repurchased			74,147,000	73,228,000
Shares repurchased, value			$ 471,311	$ 462,167
Subsequent Event [Member]
Subsequent Event [Line Items]
Renewal period of share repurchase	13 years
Stock repurchase program authorized to be repurchased	5,000,000
Expiration date of share authorization	Mar. 31, 2017
Shares repurchased		200,000
Shares repurchased, value		$ 2,200
Maximum [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Additional shares of outstanding common stock authorized	5,000,000