Subsequent Event - Additional Information (Detail) (USD $)	12 Months Ended	0 Months Ended
	Jul. 31, 2014	May 15, 2015	May 01, 2015
Postle Operating, LLC
Subsequent Event [Line Items]
Sales	$ 220,000,000
Subsequent Event
Subsequent Event [Line Items]
Common stock purchased, shares		1,000,000
Common stock price per share		$ 60.00
Aggregate purchase price of common stock		60,000,000
Closing price of common stock		$ 61.29
Percentage of issued and outstanding common stock prior to repurchase		1.90%
Subsequent Event | Postle Operating, LLC
Subsequent Event [Line Items]
Payment to acquire business			$ 144,315,000
Asset purchase agreement date			May 01, 2015