Fair Value Measurements and Disclosures about Fair Value of Financial Instruments (Balances Of Financial Assets Measured At Fair Value On Recurring And Nonrecurring) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account securities	$ 2,277	$ 3,562
Securities available for sale:	165,051	152,543
Interest rate cap contract	17	11
Loans held for sale	233	643
Total foreclosed real estate	671	1,481
Total impaired loans	5,726
Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	323
Total impaired loans	4,296
Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	321
Total impaired loans	794
Construction Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	177
Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	218
Consumer Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	241
Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	27
Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	67,151
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	91
Agency bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	15,345
Agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	42,848
Agency CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	24,630
Privately-issued CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	4,702
Privately-issued ABS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	8,122
SBA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	2,162
Fair Value, Measurements, Recurring | Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		62,933
Fair Value, Measurements, Recurring | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		69
Fair Value, Measurements, Recurring | Agency bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		16,064
Fair Value, Measurements, Recurring | Agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		43,420
Fair Value, Measurements, Recurring | Agency CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		17,541
Fair Value, Measurements, Recurring | Privately-issued CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		5,289
Fair Value, Measurements, Recurring | Privately-issued ABS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		7,227
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans		4,015
Fair Value, Measurements, Nonrecurring | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans		2,775
Fair Value, Measurements, Nonrecurring | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans		839
Fair Value, Measurements, Nonrecurring | Construction Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans		174
Fair Value, Measurements, Nonrecurring | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans		66
Fair Value, Measurements, Nonrecurring | Consumer Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans		161
Auto Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	671	1,481
Auto Loans [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		487
Auto Loans [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		231
Auto Loans [Member] | Multi-family residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		357
Auto Loans [Member] | Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		406
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate cap contract	0	0
Loans held for sale	0	0
Level 1 | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	0
Level 1 | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	0
Level 1 | Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	0
Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account securities	0	0
Securities available for sale:	91	69
Level 1 | Fair Value, Measurements, Recurring | Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 1 | Fair Value, Measurements, Recurring | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	91	69
Level 1 | Fair Value, Measurements, Recurring | Agency bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 1 | Fair Value, Measurements, Recurring | Agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 1 | Fair Value, Measurements, Recurring | Agency CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 1 | Fair Value, Measurements, Recurring | Privately-issued CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 1 | Fair Value, Measurements, Recurring | Privately-issued ABS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 1 | Fair Value, Measurements, Recurring | SBA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0
Level 1 | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 1 | Fair Value, Measurements, Nonrecurring | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 1 | Fair Value, Measurements, Nonrecurring | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 1 | Fair Value, Measurements, Nonrecurring | Construction Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 1 | Fair Value, Measurements, Nonrecurring | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 1 | Fair Value, Measurements, Nonrecurring | Consumer Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 1 | Auto Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Total impaired loans	0
Level 1 | Auto Loans [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 1 | Auto Loans [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 1 | Auto Loans [Member] | Multi-family residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 1 | Auto Loans [Member] | Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate cap contract	17	11
Loans held for sale	233	643
Level 2 | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	0
Level 2 | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	0
Level 2 | Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	0
Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account securities	2,277	3,562
Securities available for sale:	164,960	152,474
Level 2 | Fair Value, Measurements, Recurring | Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	67,151	62,933
Level 2 | Fair Value, Measurements, Recurring | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 2 | Fair Value, Measurements, Recurring | Agency bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	15,345	16,064
Level 2 | Fair Value, Measurements, Recurring | Agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	42,848	43,420
Level 2 | Fair Value, Measurements, Recurring | Agency CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	24,630	17,541
Level 2 | Fair Value, Measurements, Recurring | Privately-issued CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	4,702	5,289
Level 2 | Fair Value, Measurements, Recurring | Privately-issued ABS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	8,122	7,227
Level 2 | Fair Value, Measurements, Recurring | SBA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	2,162
Level 2 | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 2 | Fair Value, Measurements, Nonrecurring | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 2 | Fair Value, Measurements, Nonrecurring | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 2 | Fair Value, Measurements, Nonrecurring | Construction Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 2 | Fair Value, Measurements, Nonrecurring | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 2 | Fair Value, Measurements, Nonrecurring | Consumer Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	0	0
Level 2 | Auto Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Total impaired loans	0
Level 2 | Auto Loans [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 2 | Auto Loans [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 2 | Auto Loans [Member] | Multi-family residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 2 | Auto Loans [Member] | Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate cap contract	0	0
Loans held for sale	0	0
Level 3 | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	323
Level 3 | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	321
Level 3 | Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate	27
Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account securities	0	0
Securities available for sale:	0	0
Level 3 | Fair Value, Measurements, Recurring | Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 3 | Fair Value, Measurements, Recurring | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 3 | Fair Value, Measurements, Recurring | Agency bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 3 | Fair Value, Measurements, Recurring | Agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 3 | Fair Value, Measurements, Recurring | Agency CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 3 | Fair Value, Measurements, Recurring | Privately-issued CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Level 3 | Fair Value, Measurements, Recurring | Privately-issued ABS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:		0
Level 3 | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	5,726	4,015
Level 3 | Fair Value, Measurements, Nonrecurring | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	4,296	2,775
Level 3 | Fair Value, Measurements, Nonrecurring | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	794	839
Level 3 | Fair Value, Measurements, Nonrecurring | Construction Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	177	174
Level 3 | Fair Value, Measurements, Nonrecurring | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	218	66
Level 3 | Fair Value, Measurements, Nonrecurring | Consumer Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impaired loans	241	161
Level 3 | Auto Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		1,481
Total impaired loans	671
Level 3 | Auto Loans [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		487
Level 3 | Auto Loans [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		231
Level 3 | Auto Loans [Member] | Multi-family residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		357
Level 3 | Auto Loans [Member] | Land and land development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total foreclosed real estate		$ 406