Financial Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2015		Sep. 30, 2014
Assets:
Marketable securities available-for-sale	$ 9,706,000		$ 8,751,000
Cash deposits	86,400,000		94,700,000
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	439,000	[1]	10,326,000	[1]
Marketable securities available-for-sale	9,706,000	[2]	8,751,000	[2]
Total	10,145,000		19,077,000
Fair Value, Measurements, Recurring | Active Markets for Identical Instruments (Level 1)
Assets:
Cash equivalents	439,000	[1]	10,326,000	[1]
Marketable securities available-for-sale	9,706,000	[2]	8,751,000	[2]
Total	$ 10,145,000		$ 19,077,000

[1] Included in cash and cash equivalents on our condensed consolidated balance sheet at March 31, 2015 and September 30, 2014. Not included in these tables are cash deposits of $86.4 million and $94.7 million at March 31, 2015 and September 30, 2014, 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 March 31, 2015 and September 30, 2014.