Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended						0 Months Ended
	Sep. 30, 2014 Employee	Sep. 30, 2014 Non-Employee Director	Sep. 30, 2014 Restricted Stock Plan	Sep. 30, 2013 Restricted Stock Plan	Sep. 30, 2012 Restricted Stock Plan	Sep. 30, 2014 Restricted Stock Plan Employee	Dec. 02, 2013 Restricted Stock Plan Key Employees and Non-Employee Directors	Nov. 26, 2013 Restricted Stock Plan Key Employees and Non-Employee Directors
Stock-Based Compensation
Number of shares of common stock reserved for issuance			400,000
Award vesting period	3 years	3 years
Period of performance goal based on net income used for determination of vesting period	3 years
Restricted stock plan activity, number of shares
Unvested at beginning of the period (in shares)			96,750
Granted (in shares)			37,700				3,000	34,700
Forfeited / Canceled (in shares)			(450)
Vested (in shares)			(36,850)
Unvested at end of the period (in shares)			97,150	96,750
Expected to vest (in shares)			65,550
Restricted stock plan activity, Weighted Average Fair Value at Grant Date
Unvested at beginning of the period (in dollars per share)			$ 47.74
Granted (in dollars per share)			$ 52.89				$ 54.22	$ 52.78
Forfeited / Canceled (in dollars per share)			$ 56.68
Vested (in dollars per share)			$ 42.00
Unvested at end of the period (in dollars per share)			$ 51.96	$ 47.74
Expected to vest (in dollars per share)			$ 51.99
Restricted stock plan activity, other disclosures
Compensation expense			$ 1,295	$ 832	$ 1,518
Remaining unrecognized compensation expense			$ 1,627
Weighted average period for recognition			11 months 12 days
Repurchase of stock from employees (in shares)						6,284
Average purchase price (in dollars per share)						$ 53.38