Debt MIF Warehousing Agreement (Details) $ in Thousands	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Line of Credit Facility [Line Items]
Maximum Borrowing Availability under all Credit Lines	$ 225,000	$ 200,000
Notes payable bank - financial services operations	153,168	$ 168,195
Warehousing Agreement - Second Amendment to Second Amended and Restated [Member]
Line of Credit Facility [Line Items]
M/I Financial Maximum Borrowing Capacity	125,000
M/I Financial Temporary Increase Maximum Borrowing Capacity	$ 160,000
LIBOR basis points	200
Repurchase Agreement - First Amendment to Second Amended and Restated [Member]
Line of Credit Facility [Line Items]
M/I Financial Maximum Borrowing Capacity	$ 50,000
M/I Financial Temporary Increase Maximum Borrowing Capacity	$ 65,000
Minimum [Member] | Repurchase Agreement - First Amendment to Second Amended and Restated [Member]
Line of Credit Facility [Line Items]
LIBOR basis points	200
Maximum [Member] | Repurchase Agreement - First Amendment to Second Amended and Restated [Member]
Line of Credit Facility [Line Items]
LIBOR basis points	225