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	3 Months Ended
	Dec. 31, 2014
Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at September 30, 2014	4,240
Granted	46
Exercised	(385)
Cancelled/Expired	(7)
Outstanding at December 31, 2014	3,894
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at September 30, 2014	$ 8.10
Granted	$ 13.54
Exercised	$ 7.19
Cancelled/Expired	$ 10.22
Outstanding at December 31, 2014	$ 8.25
Aggregate Intrinsic Value, options exercised	$ 3,302
Weighted-Average Remaining Contractual Term in Years, Outstanding at December 31, 2014 (years)	3 years 7 months 17 days
Aggregate Intrinsic Value, Outstanding at December 31, 2014	32,414
Number of Shares, Exercisable at December 31, 2014 (shares)	2,631
Weighted-Average Exercise Price, Exercisable at December 31, 2014	$ 7.26
Weighted-Average Remaining Contractual Term in Years, Exercisable at December 31, 2014 (years)	2 years 11 months 16 days
Aggregate Intrinsic Value, Exercisable at December 31, 2014	24,481
Number of Shares, Vested and expected to vest after December 31, 2014 (shares)	3,844
Weighted-Average Exercise Price, Vested and expected to vest after December 31, 2014	$ 8.22
Weighted-Average Remaining Contractual Term in Years, Vested and expected to vest after December 31, 2014 (years)	3 years 7 months 10 days
Aggregate Intrinsic Value, Vested and expected to vest after December 31, 2014	$ 32,114