PENSION AND OTHER POSTRETIREMENT BENEFITS Components of net periodic benefit cost (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Pension Benefits
Defined Benefit Plans and Postretirement Health Benefits
Service cost	$ 1,324	$ 1,293	$ 1,137
Interest cost	1,617	1,507	1,416
Expected return on plan assets	(1,480)	(1,287)	(1,167)
Amortization of: Net transition obligations	0	0	0
Amortization of: Prior service costs	15	23	46
Amortization of: Other actuarial loss	317	316	230
Net periodic benefit cost	1,793	1,852	1,662
Postretirement Health Benefits
Defined Benefit Plans and Postretirement Health Benefits
Service cost	104	85	74
Interest cost	105	91	96
Expected return on plan assets	0	0	0
Amortization of: Net transition obligations	15	15	16
Amortization of: Prior service costs	0	0	0
Amortization of: Other actuarial loss	30	14	21
Net periodic benefit cost	$ 254	$ 205	$ 207