Intangible Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Goodwill And Intangible Assets [Line Items]
Intangible amortization expense	$ 71,437	$ 53,713	$ 46,964
Future amortization expense, 2013	77,004
Future amortization expense, 2014	77,206
Future amortization expense, 2015	76,029
Future amortization expense, 2016	72,059
Future amortization expense, 2017	$ 69,813