Stock-based Compensation - Stock options and SSARs outstanding (Details) - SSARs / Stock Options - $ / shares	3 Months Ended	9 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding at beginning of period (shares)	646,630	650,233
Exercised (shares)	(753)	(1,209)
Forfeited (shares)	(815)	(3,962)
Shares outstanding at beginning of period (shares)	645,062	645,062
Exercisable at end of period (shares)	491,699	491,699
Vested or expected to vest in the future (shares)	645,032	645,032
Weighted average exercise price of shares outstanding at beginning of period (in US$ per share)	$ 18.13	$ 18.13	$ 18.12	$ 18.12
Share-based Compensation Arrangements by Share-based Payment Award, Exercises in Period, Weighted Average Exercise Price	12.07	12.07
Share-based Compensation Arrangements by Share-based Payment Award, Forfeitures in Period, Weighted Average Exercise Price	17.81	19.81
Weighted average exercise price of shares exercisable at end of period (in US$ per share)	18.40	18.40
Weighted average exercise price of shares vested or expected to vest in the future (in US$ per share)	$ 18.13	$ 18.13