Subsequent Event - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified			1 Months Ended
	Jul. 31, 2013	Jan. 31, 2013	Sep. 04, 2013 Subsequent Event [Member]
Subsequent Event [Line Items]
Repurchase of common stock			$ 25.0
Par value of Repurchased common stock	$ 0.01	$ 0.01	$ 0.01
Date of repurchase program terminates			Jan. 31, 2015