Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Schedule Of Equity [Line Items]
Cash Dividend on Common Stock	$ 0.75	$ 0.65
Aggregated Dividend Paid	$ 38,200,000
Dividend payable date declared	Feb. 26, 2016
Common stock Dividend Payable Date	Apr. 15, 2016
Dividend payable date of record	Mar. 31, 2016
2015 Stock Repurchase Program [Member]
Schedule Of Equity [Line Items]
Authorized amount for share repurchase program	$ 100,000,000
Company repurchased, shares	0.5
Repurchase of Company stock for retirement	$ 24,800,000