Segment Data - Financial Information for Company's Segments (Parenthetical) (Detail) (Indirect Purchasers [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Jun. 30, 2013	Jun. 30, 2013
Indirect Purchasers [Member]
Segment Reporting Information [Line Items]
Settlement amount	$ 22,000	$ 22,000

Amount of judgment or settlement awarded to (against) the entity in respect of litigation.

No definition available.

Name:	us-gaap_LitigationSettlementAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration