Summary of Combined Activity Under Equity Incentive Plans (Details) - $ / shares	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, Number of Nonqualified Options, Beginning Balance	89,700	106,050	245,956
Granted, Number of Nonqualified Options Outstanding	0	0	0
Exercised, Number of Nonqualified Options Outstanding		(16,350)	(139,906)
Vested, Number of Nonqualified Options Outstanding	0	0	106,500
Outstanding, Number of Nonqualified Options, Ending Balance	89,700	89,700	106,050
Options, Outstanding, Weighted Average Exercise Price per Share, Beginning Balance	$ 17.27	$ 18.61	$ 13.90
Exercised, Weighted Average Exercise Price per Share		25.94	10.36
Options, Outstanding, Weighted Average Exercise Price per Share, Ending Balance	17.27	17.27	18.61
Outstanding, Weighted Average Grant-date fair- value per Share, Beginning Balance	95.03
Granted, Weighted Average Grant-date fair- value per Share	19.13	95.18	$ 0
Forfeited, Weighted Average Grant-date fair- value per Share	98.68	98.68
Vested, Weighted Average Grant-date fair- value per Share	95.02
Outstanding, Weighted Average Grant-date fair- value per Share, Ending Balance	$ 93.80	$ 95.03
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options, Number of Restricted Stock Awards, Beginning Balance	189,000
Granted, Number of Restricted Stock Awards	3,000	197,000
Forfeited, Number of Restricted Stock Awards	(2,500)	(8,000)
Vested, Number of Restricted Stock Awards	(47,000)
Options, Number of Restricted Stock Awards, Ending Balance	142,500	189,000