XML 64 R51.htm IDEA: XBRL DOCUMENT v2.4.0.8
Retirement and Death Benefit Plans - Additional Information (Detail) (USD $)
12 Months Ended
May 31, 2014
May 31, 2013
Compensation And Retirement Disclosure [Abstract]    
Employee retirement or disability, period over which benefits are to be paid 10 years  
Life insurance contracts, discounting rate for present value calculation 4.50% 4.00%
Life insurance contracts, current and non current amounts recognized in balance Sheet $ 5,856,000 $ 6,309,000
Life insurance contracts, amount credited to operations 152,000  
Life insurance contracts, amount charged to operations   $ 187,000