Loans (Loan Balances) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate:	$ 184,129cmsb_LoansAndLeasesReceivableRealEstate	$ 175,707cmsb_LoansAndLeasesReceivableRealEstate
Commercial	40,346	33,089
Consumer	55	103
Total	224,530	208,899
Allowance for loan losses	(740)	(923)
Net deferred loan origination fees and costs	(4)	20
Loans receivable, net	223,786	207,996
One-to-four-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate:	90,567	90,177
Multi-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate:	28,659	25,771
Non-residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate:	56,076	50,655
Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate:	174	935
Home equity and second mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate:	$ 8,653	$ 8,169

Loans And Leases Receivable Real Estate

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

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Reflects the aggregate gross carrying amount of all commercial loans and leases held in portfolio, prior to deducting deferred income and the allowance for losses on commercial loans and leases.

+ References

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Reflects the aggregate gross carrying amount of all consumer loans and leases held in portfolio, prior to deducting deferred income and the allowance for losses on consumer loans and leases.

+ References

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

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