Fair Value Measurements (Details) (Recurring basis [Member], USD $) In Thousands, unless otherwise specified	Jul. 31, 2012
Assets:
Available-for-sale securities	$ 215
SERP assets - employer	876
SERP assets - employee	16,177
Hedge derivatives	25
Total	17,293
Liabilities:
SERP liabilities - employee	16,177
Hedge derivatives	1,820
Total	17,997
Level 1 [Member]
Assets:
Available-for-sale securities	215
SERP assets - employer	876
SERP assets - employee	16,177
Hedge derivatives
Total	17,268
Liabilities:
SERP liabilities - employee	16,177
Hedge derivatives
Total	16,177
Level 2 [Member]
Assets:
Available-for-sale securities
SERP assets - employer
SERP assets - employee
Hedge derivatives	25
Total	25
Liabilities:
SERP liabilities - employee
Hedge derivatives	1,820
Total	1,820
Level 3 [Member]
Assets:
Available-for-sale securities
SERP assets - employer
SERP assets - employee
Hedge derivatives
Total
Liabilities:
SERP liabilities - employee
Hedge derivatives
Total