Summary of Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Shares
Outstanding at October 1, 2015 | shares	2,024
Granted | shares	15
Exercised | shares	(41)
Forfeited | shares	(4)
Outstanding at December 31, 2015 | shares	1,994
Exercisable at December 31, 2015 | shares	1,266
Vested and expected to vest at December 31, 2015 | shares	1,931
Weighted-average Exercise Price
Outstanding at October 1, 2015 (in dollars per share) | $ / shares	$ 46.94
Granted (in dollars per share) | $ / shares	92.71
Exercised (in dollars per share) | $ / shares	29.02
Forfeited (in dollars per share) | $ / shares	41.15
Outstanding at December 31, 2015 (in dollars per share) | $ / shares	47.66
Exercisable at December 31, 2015 (in dollars per share) | $ / shares	39.90
Vested and expected to vest at December 31, 2015 (in dollars per share) | $ / shares	$ 47.09
Weighted-average Remaining Contractual Term
Outstanding at December 31, 2015	4 years 1 month 11 days
Exercisable at December 31, 2015	3 years 6 months 18 days
Vested and expected to vest at December 31, 2015	4 years 29 days
Aggregate Intrinsic Value
Outstanding at December 31, 2015 | $	$ 92,742
Exercisable at December 31, 2015 | $	68,710
Vested and expected to vest at December 31, 2015 | $	$ 90,928