Investments - Additional Information (Detail) (U. S. Treasury Bills [Member])
|
6 Months Ended | 12 Months Ended |
---|---|---|
Nov. 30, 2013
|
May 31, 2013
|
|
U. S. Treasury Bills [Member]
|
||
Schedule of Held-to-maturity Securities [Line Items] | ||
Investment maturity period | 2 months | 3 months |