Guarantor Disclosures (Additional Information) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Ownership interest in guarantor subsidiaries	100.00%
3.60% Senior Notes Due 2022
Condensed Financial Statements, Captions [Line Items]
Minimum debt amount guaranteed by subsidiaries	5,000

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant