Segment Information - Reconciliation of Reportable Segment Assets to Corresponding Consolidated Amounts (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 30, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 749,034	$ 759,654
Cash, cash equivalents and marketable securities	65,227	214,030
Deferred tax assets	91,704	89,959
Assets held for sale	2,869	2,900
Equity method investments	24,314	24,286
Other unallocated corporate net assets	0	500
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 564,920	$ 427,979