Subsequent Event (Details) (USD $)	1 Months Ended
	Aug. 06, 2012
Subsequent Event [Line Items]
Shares of Common Stock Repurchased Between Period End Date and Filing Date	112,061
Shares of Common Stock Repurchase Executed Before the Balance Sheet Date but Settled After the Balance Sheet Date	32,550
Average Price Per Share of Common Stock Repurchased Between Period End Date and Filing Date	$ 41.31