Share Repurchase Program - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2014	Jan. 31, 2014
Equity [Abstract]
Shares repurchase program authorized		$ 65,000,000	$ 35,000,000
Common stock shares repurchased	180,400
Cost of common stock shares repurchased	$ 14,500,000
Shares repurchase program expiration date	Dec. 31, 2015
Amount of shares remaining under share repurchase program	$ 47,600,000