Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands		Dec. 31, 2015	Sep. 30, 2015
Assets:
Marketable securities available-for-sale		$ 9,662	$ 9,567
Cash deposits		90,300	85,700
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	[1]	439	439
Marketable securities available-for-sale	[2]	9,662	9,567
Total		10,101	10,006
Fair Value, Measurements, Recurring | Active Markets for Identical Instruments (Level 1)
Assets:
Cash equivalents	[1]	439	439
Marketable securities available-for-sale	[2]	9,662	9,567
Total		$ 10,101	$ 10,006

[1] Included in cash and cash equivalents on our condensed consolidated balance sheet at December 31, 2015 and September 30, 2015. Not included in these tables are cash deposits of $90.3 million and $85.7 million at December 31, 2015 and September 30, 2015, respectively.

[2] Represents securities held under a supplemental retirement and savings plan for senior management employees, which are distributed upon termination or retirement of the employees. Included in marketable securities available for sale on our condensed consolidated balance sheet at December 31, 2015 and September 30, 2015.