Share Repurchase Program - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Jul. 31, 2014	Jan. 31, 2014
Equity [Abstract]
Shares repurchase program authorized		$ 65,000,000	$ 35,000,000
Common stock shares repurchased	238,201
Cost of common stock shares repurchased	$ 20,000,000
Shares repurchase program expiration date	Dec. 31, 2015
Dollar value of shares that may yet be purchased under share repurchase program	$ 42,000,000