Leases - Additional Information (Detail) (USD $)	12 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2011
Operating Leased Assets [Line Items]
Total rental expense under operating leases	$ 1,700,000	$ 1,500,000	$ 1,500,000
Rental Income	$ 648,000	$ 1,107,000	$ 912,000
Walbridge Ohio Facility
Operating Leased Assets [Line Items]
Lease expiration date	Apr. 30, 2015
Lease extension period	3 years
Lease expiration, automatic extension end date	Apr. 30, 2027
Michigan
Operating Leased Assets [Line Items]
Lease extension period	5 years
Lease expiration date	2018-09
Lease expiration, automatic extension end date	2043-09