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Fair Value - Additional Information (Detail) (USD $)
|
Feb. 28, 2014
|
May 31, 2013
|
|---|---|---|
| Fair Value Measurements [Line Items] | ||
| Long-term debt at fair value including current maturities | $ 415,517,000 | $ 421,056,000 |
| Long-term debt at carrying amount including current maturities | $ 406,484,000 | $ 407,328,000 |