Bank's Investment in Trust Preferred Securities (Parenthetical) (Detail)	Mar. 31, 2013
Banks, thrifts or other depository institutions to all projected defaults
Investment Holdings [Line Items]
Collateral recovery probability percentage	10.00%
Insurance Companies to all projected insurance defaults
Investment Holdings [Line Items]
Collateral recovery probability percentage	15.00%

Percentage of expected recoveries to remaining performing collateral

No definition available.

Name:	mfsf_PercentageOfExpectedRecoveriesToRemainingPerformingCollateral
Namespace Prefix:	mfsf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant