Reconciliation of Reportable Segment Assets to Corresponding Consolidated Amounts (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Sep. 30, 2011
Segment Reporting, Asset Reconciling Item [Line Items]
Investments in cash equivalents, marketable securities, joint ventures, and other unallocated corporate net assets	$ 245,627	$ 247,951
Total assets	645,323	636,958
Operating Segments, Total
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 399,696	$ 389,007