Discontinued Operations - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 11, 2013	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Discontinued Operations [Line Items]
Consideration received from the sale of assets	$ 1.6
Gross amount of assets sold	1.9
Amount received from the sale of assets				1.4
Amount of consideration to be received up on settlement of post closing adjustments		0.2		0.2
Transition support agreement, period	90 days
Loss recorded related to net present value accretion on future lease payments		0.2		0.2
Income recorded due to execution of sublease for vacated facility			$ 0.7		$ 0.7