Weighted Average Shares - Calculation of Weighted Average Shares (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Basic weighted-average common shares outstanding	85,338	86,296	86,858
Effect of dilutive stock options	1,734	1,695	2,213
Diluted weighted-average common and common-equivalent shares outstanding	87,072	87,991	89,071