Employee Benefit Plan (Details Textual) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Benefit Plan (Textual) [Abstract]
Defined Contribution Plan Contribution By Employee Percentage Maximum	100.00%
Employees contributions	$ 1.00
Matching contribution by company for each dollar contributed by employee under the plan	0.50
Percentage of salary contributions for employee, maximum	6.00%
Percentage of maximum match	3.00%
Period of Vesting of contributions	5 years
Percentage of Vesting of contributions	20.00%
Payments on behalf of the defined contribution plan	$ 115,000	$ 96,000	$ 96,000

Defined contribution plan contribution by employee.

No definition available.

Name:	mfi_DefinedContributionPlanContributionByEmployee
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Period Type:	duration

Defined contribution plan contribution by employee percentage maximum.

No definition available.

Name:	mfi_DefinedContributionPlanContributionByEmployeePercentageMaximum
Namespace Prefix:	mfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Defined contribution plan employers matching contribution years of vesting.

No definition available.

Name:	mfi_DefinedContributionPlanEmployersMatchingContributionYearsOfVesting
Namespace Prefix:	mfi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Defined contribution plan matching contribution by employer.

No definition available.

Name:	mfi_DefinedContributionPlanMatchingContributionByEmployer
Namespace Prefix:	mfi_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

Name:	mfi_EmployeeBenefitPlanTextualAbstract
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Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of employer's matching contributions to a defined contribution plan that vests in a given year.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Maximum percentage of employee gross pay, by the terms of the plan, that the employer may contribute to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration