Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Employee Benefit Plans
Maximum contribution by employee (as a percent)	75.00%
Employer's matching contribution (as a percent)	4.00%
Employer's contribution	$ 867	$ 842	$ 800

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration