Share-Based Payments - Summary of Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Shares
Outstanding at October 1, 2016 | shares	1,521
Exercised | shares	(100)
Outstanding at December 31, 2016 | shares	1,421
Exercisable at December 31, 2016 | shares	1,131
Vested and expected to vest at December 31, 2016 | shares	1,403
Weighted-average Exercise Price
Outstanding at October 1, 2016 (in dollars per share) | $ / shares	$ 52.37
Exercised (in dollars per share) | $ / shares	36.52
Outstanding at December 31, 2016 (in dollars per share) | $ / shares	53.49
Exercisable at December 31, 2016 (in dollars per share) | $ / shares	48.42
Vested and expected to vest at December 31, 2016 (in dollars per share) | $ / shares	$ 53.22
Weighted-average Remaining Contractual Term
Outstanding at December 31, 2016	3 years 7 months 20 days
Exercisable at December 31, 2016	3 years 3 months 20 days
Vested and expected to vest at December 31, 2016	3 years 7 months 15 days
Aggregate Intrinsic Value
Outstanding at December 31, 2016 | $	$ 93,412
Exercisable at December 31, 2016 | $	80,056
Vested and expected to vest at December 31, 2016 | $	$ 92,598