Pension Plan - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	May 31, 2013	Feb. 28, 2013	Jul. 31, 2012
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Employees covered under Non Contributory Pension Plan	9.00%
Compensation period preceding retirement and termination	5 years
Minimum required contribution to the plan is approximately	$ 0
Company expect to make cash contribution to the plan		3.0
Number of years used for calculating pension plan liability			25 years
Predecessor [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Number of years used for calculating pension plan liability			24 months
Minimum [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Company expect to make cash contribution to the plan	2.0
Maximum [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Company expect to make cash contribution to the plan	$ 3.0