Employee Benefit Plans 401(k) Plan Narrative (Details) (401(k) Plan [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
401(k) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employees contribution, maximum	100.00%
Matching contribution	50.00%
Percentage of employer matching contribution to employees compensation	6.00%
Matching contributions vesting period	5 years
Expense attributable to the plan	$ 340	$ 355	$ 308

Percentage of employer matching contribution on first specified percentage contributed to the plan by the employee.

No definition available.

Name:	mbrg_DefinedContributionPlanEmployerMatchingContributionMaximum
Namespace Prefix:	mbrg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period over which matching contributions vest to the employee.

+ References

No definition available.

+ Details

Name:	mbrg_DefinedContributionPlanEmployersMatchingContributionVestingPeriod
Namespace Prefix:	mbrg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	mbrg_DefinedContributionPlanMaximumAnnualContributionByEmployeePercent
Namespace Prefix:	mbrg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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