Fair Value Measurement - Additional Information (Detail)	6 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($) Loans	Sep. 30, 2015 USD ($) Loans
Fair Value Disclosures [Abstract]
Number of impaired loans | Loans	208	211
Impaired loans, carrying value	$ 27,000,000	$ 28,700,000
Impaired loans, valuation allowance	760,000	568,000
Impaired loans, net fair value	$ 26,200,000	$ 28,100,000