Share-Based Compensation - Summary of Stock Option Activity (Details) (Stock Options, USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended	12 Months Ended
	Mar. 31, 2014	Sep. 30, 2013
Stock Options
Number of Options:
Outstanding at October 1, 2013 (shares)	989
Granted (shares)	0
Exercised (shares)	(57)
Forfeited (shares)	(17)
Outstanding at March 31, 2014 (shares)	915	989
Exercisable at March 31, 2014 (shares)	725
Wtd. Avg. Exercise Price (in dollars per share):
Outstanding at October 1, 2013 (dollars per share)	$ 33.21
Granted (dollars per share)	$ 0.00
Exercised (dollars per share)	$ 27.16
Forfeited (dollars per share)	$ 40.26
Outstanding at March 31, 2014 (dollars per share)	$ 33.52	$ 33.21
Exercisable at March 31, 2014 (dollars per share)	$ 31.80
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Wtd. Avg. Remaining Contractual Life (Years)	5 years 6 months 0 days	5 years 10 months 24 days
Wtd. Avg. Remaining Contractual Life (Years), Exercisable at March 31, 2014	5 years 0 months 0 days
Aggregate Intrinsic Value	$ 15,286	$ 21,592
Aggregate Intrinsic Value, Exercised	1,255
Aggregate Intrinsic Value, Exercisable at March 31, 2014	$ 13,478