Shareholders' Equity Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
	Oct. 27, 2016	Mar. 31, 2017	Mar. 31, 2016
Subsequent Event [Line Items]
Repurchase and retirement of common stock		$ 21,807
Repurchase and retirement of common stock (shares)		256
Shares remaining available for repurchases (shares)		7,207
Cash dividend paid during period, per share (in dollars per share)		$ 0.58	$ 0.55
Dividends declared (in dollars per share)	$ 0.58
Common stock excluded from calculation of diluted earnings per share (shares)		3,167	1,594