CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) (Parenthetical)	Jun. 30, 2012
Supplemental noncash disclosures:
Conversion of subordinated note to Common stock (in shares)	491,830

Number of common stock shares as a result of the conversion of subordinated note.

No definition available.

Name:	mcbc_ConversionOfSubordinatedNoteToCommonStock
Namespace Prefix:	mcbc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant