Cash and Equivalents - Components of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Cash and Cash Equivalents [Line Items]
Cash on hand - Restricted	$ 1,000	$ 1,000
Total	53,422	49,973	$ 49,516	$ 43,047
Cash and Equivalents [Member]
Cash and Cash Equivalents [Line Items]
Overnight repurchase agreements	25,147	25,436
Cash on hand - Unrestricted	28,275	24,537
Total	53,422	49,973
Other Assets [Member]
Cash and Cash Equivalents [Line Items]
Cash on hand - Restricted	1,000	1,000
Total	$ 1,000	$ 1,000