Marketable Securities Summary of Marketable Securities Including Accrued Interest Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 6,096	$ 6,137
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(13)	(3)
Fair Value	6,083	6,135
Corporate securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,398	2,394
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	2,398	2,394
Other debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27	39
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	27	39
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,671	3,704
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(13)	(3)
Fair Value	$ 3,658	$ 3,702

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Paragraph 2
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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