RESTRICTION ON CASH AND DUE FROM BANKS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
RESTRICTION ON CASH AND DUE FROM BANKS
Required reserve funds in cash or on deposit with the Federal Reserve Bank	$ 14,357	$ 7,474

Represents the amount of reserve funds in cash or on deposit with the Federal Reserve Bank, required to be maintained by the entity.

No definition available.

Name:	msfg_RequiredReserveFundsInCashOrOnDepositWithFederalReserveBank
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant