Stock-based Compensation (Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable) (Details) (Options, USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Jun. 30, 2014
Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at September 30, 2013	5,351
Granted	468
Exercised	(1,239)
Cancelled/Expired	(121)
Outstanding at June 30, 2014	4,459
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at September 30, 2013	$ 7.51
Granted	$ 11.22
Exercised	$ 6.77
Cancelled/Expired	$ 10.18
Outstanding at June 30, 2014	$ 8.03
Aggregate Intrinsic Value, options exercised	$ 7,632
Weighted-Average Remaining Contractual Term in Years, Outstanding at June 30, 2014 (years)	3 years 11 months 9 days
Aggregate Intrinsic Value, Outstanding at June 30, 2014	30,036
Number of Shares, Exercisable at June 30, 2014 (shares)	2,759
Weighted-Average Exercise Price, Exercisable at June 30, 2014	$ 6.87
Weighted-Average Remaining Contractual Term in Years, Exercisable at June 30, 2014 (years)	3 years 1 month 17 days
Aggregate Intrinsic Value, Exercisable at June 30, 2014	21,800
Number of Shares, Vested and expected to vest after June 30, 2014 (shares)	4,384
Weighted-Average Exercise Price, Vested and expected to vest after June 30, 2014	$ 8.00
Weighted-Average Remaining Contractual Term in Years, Vested and expected to vest after June 30, 2014 (years)	3 years 10 months 28 days
Aggregate Intrinsic Value, Vested and expected to vest after June 30, 2014	$ 29,689