Debt MIF Warehousing Agreement (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Maximum Borrowing Availability under all Credit Lines	$ 210,000	$ 225,000
Notes payable bank - financial service operations	$ 108,594	$ 153,168
Warehousing Agreement - Third Amendment to Second Amended and Restated [Member]
Debt Instrument [Line Items]
Basis point spread on variable rate under warehouse	2.00%
Line of Credit Facility, Maximum Borrowing Capacity	$ 125,000
M/I Financial Temporary Increase Maximum Borrowing Capacity	$ 160,000
Line of Credit Facility, Expiration Date	Jun. 19, 2020
Repurchase Agreement - First Amendment to Second Amended and Restated [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 50,000
M/I Financial Temporary Increase Maximum Borrowing Capacity	$ 65,000
Line of Credit Facility, Expiration Date	Oct. 28, 2019
Minimum [Member] \| Repurchase Agreement - First Amendment to Second Amended and Restated [Member]
Debt Instrument [Line Items]
Basis point spread on variable rate under warehouse	2.00%
Maximum [Member] \| Repurchase Agreement - First Amendment to Second Amended and Restated [Member]
Debt Instrument [Line Items]
Basis point spread on variable rate under warehouse	2.25%

M/I Financial Temporary Increase Maximum Borrowing Capacity

No definition available.

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Namespace Prefix:	mho_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Maximum Borrowing Availability under all Credit Lines

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Carrying value as of the balance sheet date of the outstanding short-term borrowings under a revolving line of credit used by mortgage bankers to finance the origination or purchase of loans.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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