Stock Repurchases - Additional Information (Detail) (USD $)	6 Months Ended	13 Months Ended
	Jun. 30, 2012 Year	Feb. 09, 2012
Stock Repurchase Programs [Line Items]
Amount of authorized repurchase of outstanding common stock		$ 100,000,000
Maximum prevailing market price period, years	2
Common stock repurchased, Shares Outstanding	1,372,853
Stock Repurchases During Period Value	$ 50,025,000