Reconciliation of Reportable Segment Operating Income (Loss) and Segment Assets to Corresponding Consolidated Amounts (Detail) (USD $) In Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2009	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Revenues from External Customers and Long-Lived Assets [Line Items]
Other unallocated corporate expenses		$ 1,135	$ 778	$ 6,592
Amortization of acquired intangible assets		2,411	1,969	4,637
Impairment of goodwill	71,800			71,800
Impairment of long-lived assets	35,100			35,512
Restructuring charges		1,036	2,529	12,806
Operating income (loss)		79,597	47,007	(228,028)
Investments in cash equivalents, marketable securities, joint ventures and other unallocated corporate net assets		247,613	180,228
Total assets		636,620	518,224
Operating Segments, Total
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating income (loss)		84,179	52,283	(96,681)
Total assets		$ 389,007	$ 337,996	$ 265,474