Property, Plant and Equipment - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2011
Depreciation and Amortization Expenses For Property Plant And Equipment [Line Items]
Property, plant and equipment disposed	$ 36,000	$ 19,000
Accumulated depreciation of disposed property, plant and equipment	34,000	18,000
Depreciation expense	44,326	38,651	40,637
Interest expense capitalized	$ 2,355	$ 1,138	$ 10