v3.19.1

Note 3 - Stock-based Compensation Plan - SOSARs Activity (Details) - Stock Appreciation Rights (SARs) [Member] - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
SOSARs Outstanding, Balance (in shares)	347,379
SOSARs Outstanding, Weighted average base price (in dollars per share)	$ 8.78	$ 8.78
Granted (in shares)
Granted, Weighted average base price (in dollars per share)
Exercised (in shares)	(2,166)
Exercised, Weighted average base price (in dollars per share)	$ 9.44
Forfeited (in shares)
Forfeited, Weighted average base price (in dollars per share)
Expired (in shares)
Expired, Weighted average base price (in dollars per share)
SOSARs Outstanding, Balance (in shares)	345,213	347,379
SOSARs Exercisable, March 31, 2019 (in shares)	152,879
SOSARs Exercisable, Weighted average base price (in dollars per share)	$ 6.41

The number of shares into which fully or partially vested equity instruments other than options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

The weighted-average base price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of non-option equity instruments outstanding and currently exercisable under the stock option plan.

+ References

No definition available.

+ Details

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- Definition

Weighted average base price at which grantees could have acquired the underlying shares with respect to non-option equity instruments of the plan that expired.

+ References

No definition available.

+ Details

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Namespace Prefix:	mbtf_
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- Definition

The weighted average base price of non-option forfeitures in period.

+ References

No definition available.

+ Details

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Namespace Prefix:	mbtf_
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Period Type:	duration

- Definition

The weighted average base price of non-option grants in period.

+ References

No definition available.

+ Details

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Namespace Prefix:	mbtf_
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- Definition

The weighted average base price of non-option awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Weighted average base price at which option holders acquired shares when converting their non-option equity instruments into shares.

+ References

No definition available.

+ Details

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- Definition

Number of non-option equity instruments exercised by participants.

+ References

+ Details

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- Definition

Number of shares under non-option equity instrument agreements for which rights to exercise lapsed.

+ References

+ Details

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- Definition

Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

+ References

+ Details

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- Definition

Net number of non-option equity instruments granted to participants.

+ References

+ Details

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

MBT FINANCIAL CORP 10-Q