Debt (Details 1) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012
Carrying Amount [Member]
Estimated fair values of the Company's lines of credit and long-term debt
Lines of credit	$ 15,032
Long-term debt	768,412
Liabilities, Fair Value, Total	783,444
Fair Value [Member]
Estimated fair values of the Company's lines of credit and long-term debt
Lines of credit	15,032
Long-term debt	749,508
Liabilities, Fair Value, Total	$ 764,540

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. Fair value of lines of credit at the balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Line-of-Credit Arrangement

-URI http://asc.fasb.org/extlink&oid=6517033

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