Share Repurchase Program - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Jul. 31, 2014	Jan. 31, 2014
Equity [Abstract]
Shares repurchase program authorized		$ 65,000,000	$ 35,000,000
Common stock shares repurchased	117,400
Cost of common stock shares repurchased	8,900,000
Shares repurchase program expiration date	Dec. 31, 2015
Amount of shares remaining under share repurchase program	$ 53,100,000