PENSION AND EMPLOYEE BENEFITS PLANS: (Tables)
 6 Months Ended
May 31, 2014
Compensation and Retirement Disclosure [Abstract]  
Schedule of components of net periodic pension costs
The components of net periodic pension costs pertaining to the Company's single employer benefit plans during the three months ended May 31, 2014 and 2013 were as follows:
 
Three Months Ended
 
Six Months Ended
 
May 31, 2014
 
May 31, 2013
 
May 31, 2014
 
May 31, 2013
Service cost
$
345

 
$
146

 
$
552

 
$
308

Interest cost
159

 
37

 
227

 
77

Expected return on plan assets
(17
)
 
(15
)
 
(34
)
 
(31
)
Amortization of net loss
140

 
—

 
176

 
—

Net periodic pension costs
$
627

 
$
168

 
$
921

 
$
354