Guarantor Financial Information (Details) (2019 Senior Notes, USD $)	1 Months Ended	2 Months Ended
Oct. 31, 2013	Apr. 30, 2011	Mar. 31, 2011	Oct. 31, 2013 Guarantor Subsidiaries Guarantee on senior notes	Apr. 30, 2011 Guarantor Subsidiaries Guarantee on senior notes
Performance and payment guaranteed
Aggregate principal amount of notes issued	$ 250,000,000	$ 50,000,000	$ 300,000,000	$ 250,000,000	$ 350,000,000

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

No definition available.

Name:	us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration