Summary of Significant Accounting Policies - Components of Cash, Cash Equivalents and Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Cash on hand -
Restricted	$ 1,000	$ 1,000
Total Restricted Cash	1,000	1,000
Unrestricted	12,179	18,101
Total Cash and Cash Equivalents	44,282	31,593	23,626	37,879
Cash on hand -
Restricted	1,000	1,000
Total Restricted Cash	1,000	1,000
Unrestricted	12,179	18,101
Total Cash and Cash Equivalents	44,282	31,593	23,626	37,879
Overnight Repurchase Agreements [Member]
Cash on hand -
Overnight repurchase agreements	$ 32,103	$ 13,492