STOCK-BASED COMPENSATION AND STOCK REPURCHASE PROGRAM (Narrative) (Details) (USD $)	6 Months Ended	89 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015
Stock option expenses	$ 0us-gaap_StockOptionPlanExpense	$ 0us-gaap_StockOptionPlanExpense
Stock award expenses	9,000us-gaap_RestrictedStockExpense	9,000us-gaap_RestrictedStockExpense
Cost of shares repurchased by ESOP trust	2,300,000
Average cost of shares repurchased (per share)	$ 10.58
Description of loan with respect to employee stock ownership plan	The ESOP trust purchased 217,863 shares of common stock in the open market using proceeds of a loan from the Company. The total cost of shares purchased by the ESOP trust was $2.3 million, reflecting an average cost per share of $10.58. The Bank will make cash contributions to the ESOP on an annual basis sufficient to enable the ESOP to make the required loan payments to the Company. The loan bears a variable interest rate that adjusts annually every January 1^st to the then published Prime Rate (3.25% at January 1, 2015) with principal and interest payable annually in equal installments over thirty years. The loan is secured by shares of the Company's stock.
Interest rate of loan with respect to employee stock ownership plan	3.25%		3.25%
Shares allocated	128,436		128,436
Suspense shares	89,426		89,426
Fair value of unallocated shares	752,967		752,967
ESOP compensation expense	$ 53,000	$ 48,000
Total ESOP shares	217,863		217,863
Stock Options [Member]
Vesting period	5 years
Expiration period	10 years
Term of treasury security	7 years
Restricted shares [Member]
Vesting period	5 years
Second Repurchase Program
Maximum stock repurchase authorization (as a percent)			5.00%
Stock authorized to be repurchased (in shares)	129,924		129,924
Stock repurchased during period (in shares)			81,000
Remaining shares available to be repurchased	48,924		48,924
Common stock average cost (in dollars per share)			$ 8.33

STOCK-BASED COMPENSATION AND STOCK REPURCHASE PROGRAM (Narrative) (Details) (USD $)

6 Months Ended

89 Months Ended

Mar. 31, 2015

Mar. 31, 2014

Mar. 31, 2015

Stock option expenses

$ 0us-gaap_StockOptionPlanExpense

Stock award expenses

9,000us-gaap_RestrictedStockExpense

Cost of shares repurchased by ESOP trust

2,300,000mgyr_EmployeeStockOwnershipPlanESOPValueInESOP

Average cost of shares repurchased (per share)

$ 10.58us-gaap_EmployeeStockOwnershipPlanESOPWeightedAveragePurchasePriceOfSharesPurchased

Description of loan with respect to employee stock ownership plan

The ESOP trust purchased 217,863 shares of common stock in the open market using proceeds of a loan from the Company. The total cost of shares purchased by the ESOP trust was $2.3 million, reflecting an average cost per share of $10.58. The Bank will make cash contributions to the ESOP on an annual basis sufficient to enable the ESOP to make the required loan payments to the Company. The loan bears a variable interest rate that adjusts annually every January 1^st to the then published Prime Rate (3.25% at January 1, 2015) with principal and interest payable annually in equal installments over thirty years. The loan is secured by shares of the Company's stock.

Interest rate of loan with respect to employee stock ownership plan

3.25%mgyr_InterestRateOfLoanWithRespectToEmployeeStockOwnershipPlan

Shares allocated

128,436us-gaap_EmployeeStockOwnershipPlanESOPNumberOfAllocatedShares

Suspense shares

89,426us-gaap_EmployeeStockOwnershipPlanESOPNumberOfSuspenseShares

Fair value of unallocated shares

752,967us-gaap_EmployeeStockOwnershipPlanESOPDeferredSharesFairValue

ESOP compensation expense

$ 53,000us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense

$ 48,000us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense

Total ESOP shares

217,863us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP

Stock Options [Member]

Vesting period

5 years

Expiration period

10 years

Term of treasury security

7 years

Restricted shares [Member]

Vesting period

5 years

Second Repurchase Program

Maximum stock repurchase authorization (as a percent)

5.00%mgyr_MaximumPercentageStockRepurchaseAuthorisation
/ us-gaap_ShareRepurchaseProgramAxis
= mgyr_ShareRepurchaseSecondProgramMember

Stock authorized to be repurchased (in shares)

129,924us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
/ us-gaap_ShareRepurchaseProgramAxis
= mgyr_ShareRepurchaseSecondProgramMember

Stock repurchased during period (in shares)

81,000us-gaap_TreasuryStockSharesAcquired
/ us-gaap_ShareRepurchaseProgramAxis
= mgyr_ShareRepurchaseSecondProgramMember

Remaining shares available to be repurchased

48,924us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased
/ us-gaap_ShareRepurchaseProgramAxis
= mgyr_ShareRepurchaseSecondProgramMember

Common stock average cost (in dollars per share)

$ 8.33us-gaap_TreasuryStockAcquiredAverageCostPerShare
/ us-gaap_ShareRepurchaseProgramAxis
= mgyr_ShareRepurchaseSecondProgramMember