Shares Repurchased - Additional Information (Detail) - USD ($)		12 Months Ended
	Apr. 27, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 29, 2014
Class of Stock [Line Items]
Repurchased common stock, value		$ 39,379,000	$ 24,116,000	$ 6,531,000
Three-Year Share Repurchase Program [Member]
Class of Stock [Line Items]
Common stock purchase authorized amount					$ 100,000,000
Share repurchase program, increase in authorized amount	$ 60,000,000
Share repurchase program, extended term date	Apr. 27, 2019
Repurchased common stock, shares		3,778,932	1,190,356	415,834
Repurchased common stock, value		$ 39,379,000	$ 24,116,000	$ 6,531,000
Dollar amount remaining for future share repurchases		$ 96,505,000