Summary of Combined Activity Under Equity Incentive Plans (Details) - $ / shares	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, Number of Nonqualified Options, Beginning Balance	89,700	89,700	106,050
Granted, Number of Nonqualified Options Outstanding	69,300
Exercised, Number of Nonqualified Options Outstanding	0	0	(16,350)
Vested, Number of Nonqualified Options Outstanding	0	0	0
Outstanding, Number of Nonqualified Options, Ending Balance	159,000	89,700	89,700
Options, Outstanding, Weighted Average Exercise Price per Share, Beginning Balance	$ 17.27	$ 17.27	$ 18.61
Granted, Weighted Average Exercise Price per Share	14.87
Exercised, Weighted Average Exercise Price per Share			25.94
Options, Outstanding, Weighted Average Exercise Price per Share, Ending Balance	16.23	17.27	17.27
Outstanding, Weighted Average Grant-date fair- value per Share, Beginning Balance	93.80	95.03
Granted, Weighted Average Grant-date fair- value per Share	14.84	19.13	95.18
Forfeited, Weighted Average Grant-date fair- value per Share	77.33	98.68	98.68
Vested, Weighted Average Grant-date fair- value per Share	90.73	95.02
Outstanding, Weighted Average Grant-date fair- value per Share, Ending Balance	$ 39.98	$ 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	142,500	189,000
Granted, Number of Restricted Stock Awards	182,400	3,000	197,000
Forfeited, Number of Restricted Stock Awards	(2,250)	(2,500)	(8,000)
Vested, Number of Restricted Stock Awards	(49,000)	(47,000)
Options, Number of Restricted Stock Awards, Ending Balance	273,650	142,500	189,000