Guarantees - Additional Information (Detail) (USD $)	Sep. 30, 2014
Guarantor Obligations [Line Items]
Guarantor obligations, standby letters of credit	$ 195,700,000
Liability related to standby letters of credit	720,000
Secured [Member]
Guarantor Obligations [Line Items]
Guarantor obligations, standby letters of credit	$ 131,100,000
Percent of secured letters of credit	67.00%

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

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