Debt MIF Warehousing Agreement (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Maximum Borrowing Availability under all Credit Lines	$ 160,000	$ 185,000
Notes payable bank - financial service operations	89,518	$ 152,895
Warehousing Agreement - Second Amended and Restated [Member]
Debt Instrument [Line Items]
M/I Financial Maximum Borrowing Capacity	125,000
M/I Financial Temporary Increase Maximum Borrowing Capacity	$ 150,000
LIBOR basis points	250
Warehousing Agreement - First Amendment to Second Amended and Restated [Member]
Debt Instrument [Line Items]
LIBOR basis points	237.5
Debt Instrument, Basis Spread on Variable Rate	2.75%
Repurchase Agreement [Member]
Debt Instrument [Line Items]
M/I Financial Maximum Borrowing Capacity	$ 15,000
Repurchase Agreement - Amendment No. 4 [Member]
Debt Instrument [Line Items]
M/I Financial Maximum Borrowing Capacity	$ 35,000
Minimum [Member] | Repurchase Agreement [Member]
Debt Instrument [Line Items]
LIBOR basis points	250
Maximum [Member] | Repurchase Agreement [Member]
Debt Instrument [Line Items]
LIBOR basis points	275