XML 102 R64.htm IDEA: XBRL DOCUMENT v3.2.0.727
Stock Based Compensation (Details 3) - $ / shares
12 Months Ended
May. 31, 2015
May. 31, 2014
May. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward      
Unvested at June 1, 2014 480,157    
Restricted stock granted 154,115 191,964 220,391
Restricted stock vested (192,920)    
Restricted stock forfeited (2,310)    
Unvested at May 31, 2015 439,042 480,157  
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value [Abstract]      
Unvested at June 1, 2014 $ 91.46    
Restricted stock granted 148.89 $ 100.8 $ 85.45
Restricted stock vested 88.33    
Restricted stock forfeited 116.12    
Unvested at May 31, 2015 $ 112.87 $ 91.46