Retirement and Savings Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	May 31, 2013	Feb. 28, 2013
Employee Benefit And Retirement Plans [Line Items]
Number of defined contribution retirement plans	1
Pension Plans, Defined Benefit
Employee Benefit And Retirement Plans [Line Items]
Employer expected contribution to defined benefit plans		$ 3.1
Employer contribution made to defined benefit plan	0.8
Employer expected contribution to defined benefit plans		2.0
Pension Plans, Defined Benefit | Minimum
Employee Benefit And Retirement Plans [Line Items]
Employer expected contribution to defined benefit plans		1.1
Other Postretirement Benefit Plans, Defined Benefit
Employee Benefit And Retirement Plans [Line Items]
Employer expected contribution to defined benefit plans		0.1
Employer contribution made to defined benefit plan	$ 0.1