Stock Option Activity and Related Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2011 Year
Number of Options
Beginning Balance	11,866
Options granted	0
Options cancelled	(12)
Options exercised	(1,386)
Ending Balance	10,468
Exercisable at end of the period	10,172
Expected to vest after end of the period	296
Weighted-Average Exercise Price
Beginning Balance	$ 108.64
Options granted	$ 0
Options cancelled	$ 152.08
Options exercised	$ 65.66
Ending Balance	$ 114.28
Exercisable at end of the period	$ 113.23
Expected to vest after end of the period	$ 150.19
Weighted - Average Remaining Contractual Term (in years)
Ending Balance (in years)	2.24
Exercisable at end of the period (in years)	2.20
Expected to vest after end of the period (in years)	3.54
Aggregate Intrinsic Value
Ending Balance	$ 3,043,317
Exercisable at end of the period	2,967,830
Expected to vest after end of the period	$ 75,487