Summary of Significant Accounting Policies (Summary Of Estimated Fair Value Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013
Carrying value	$ 625,600	$ 795,928
6.50% Notes [Member]
Carrying value	215,000	390,000
Fair value	223,600	409,500
Industrial Development Bonds [Member]
Carrying value	41,200	41,200
Fair value	48,003	47,512
Other Long-Term Debt [Member]
Carrying value	5,163	5,383
Fair value	$ 5,758	$ 5,852

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant