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Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy with buffer as defined by regulatory framework.

No definition available.

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Amount of minimum Common Equity Tier 1 risk-based capital required for capital adequacy with buffer as defined by regulatory framework.

No definition available.

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The minimum Common Equity Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy with buffer as defined by regulatory framework.

No definition available.

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Data Type:	xbrli:pureItemType
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The Common Equity Tier I capital ratio (Common Equity Tier I capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

No definition available.

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Data Type:	xbrli:pureItemType
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Amount of minimum Tier 1 leverage capital required for capital adequacy with buffer as defined by regulatory framework.

No definition available.

Name:	mbin_TierOneLeverageCapitalRequiredForCapitalAdequacyWithBuffer
Namespace Prefix:	mbin_
Data Type:	xbrli:monetaryItemType
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Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy with buffer as defined by regulatory framework.

No definition available.

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Namespace Prefix:	mbin_
Data Type:	xbrli:pureItemType
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Amount of minimum Tier 1 risk-based capital required for capital adequacy with buffer as defined by regulatory framework.

No definition available.

Name:	mbin_TierOneRiskBasedCapitalRequiredForCapitalAdequacyWithBuffer
Namespace Prefix:	mbin_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy with buffer as defined by regulatory framework.

No definition available.

Name:	mbin_TierOneRiskBasedCapitalRequiredForCapitalAdequacyWithBufferToRiskWeightedAssets
Namespace Prefix:	mbin_
Data Type:	xbrli:pureItemType
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Period Type:	instant

Amount of total capital as defined by regulatory framework.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

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Amount of minimum total risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework.

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Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework.

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No definition available.

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Ratio of Common Equity Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

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Amount of minimum Common Equity Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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No definition available.

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No definition available.

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Amount of Tier 1 leverage capital as defined by regulatory framework.

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Amount of minimum Tier 1 leverage capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of Tier 1 capital to average assets as defined by regulatory framework.

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Amount of Tier 1 risk-based capital as defined by regulatory framework.

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No definition available.

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Amount of minimum Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.