Capital Stock (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2012 Item	Sep. 30, 2011 Item	Sep. 30, 2010
Capital Stock
Number of authorized classes of stock	2	2
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Par value of preferred stock (in dollars per share)	$ 0.01	$ 0.01
Shares of preferred stock authorized	5,000,000	5,000,000
Option activity
Outstanding at the beginning of the period (in shares)	302,300	391,688	457,917
Exercised (in shares)	(84,300)	(89,388)	(66,229)
Outstanding at the end of the period (in shares)	218,000	302,300	391,688
Average Price Per Share
Outstanding at the beginning of the period (in dollars per share)	$ 10.84	$ 9.64	$ 8.85
Exercised (in dollars per share)	$ 6.12	$ 5.59	$ 4.20
Outstanding at the end of the period (in dollars per share)	$ 12.66	$ 10.84	$ 9.64
Aggregate Option Price
Outstanding at the beginning of the period (in dollars)	$ 3,276	$ 3,776	$ 4,054
Exercised (in dollars)	(516)	(500)	(278)
Outstanding at the end of the period (in dollars)	$ 2,760	$ 3,276	$ 3,776
Stock options
Capital Stock
Options issued, outstanding and exercisable (in shares)	218,000
1998 Stock Incentive Plan
Capital Stock
Term of award	10 years
Shares of common stock reserved for issuance	1,050,000
1998 Stock Incentive Plan | Minimum
Capital Stock
Award vesting period	2 years
1998 Stock Incentive Plan | Maximum
Capital Stock
Award vesting period	4 years
1998 Stock Incentive Plan | Stock options
Capital Stock
Options issued, outstanding and exercisable (in shares)	198,000
1998 Non-Employee Director Stock Option Plan
Capital Stock
Award vesting period	3 years
Term of award	10 years
Shares of common stock reserved for issuance	150,000
1998 Non-Employee Director Stock Option Plan | Stock options
Capital Stock
Options issued, outstanding and exercisable (in shares)	20,000