Fair Value Measurements Fair Value of Financial Instrument Assumptions (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value of Financial Instrument Assumptions [Line Items]
Letters of Credit Potential Commitments, Amount	$ 33,626	$ 25,833
First Amendment to New Unsecured Credit Facility [Member]
Fair Value of Financial Instrument Assumptions [Line Items]
Homebuilding Line of Credit Facility, Current Borrowing Capacity	300,000
Warehousing Agreement - First Amendment to Amended and Restated [Member]
Fair Value of Financial Instrument Assumptions [Line Items]
M/I Financial Maximum Borrowing Capacity	110,000
Repurchase Agreement [Member]
Fair Value of Financial Instrument Assumptions [Line Items]
M/I Financial Maximum Borrowing Capacity	$ 15,000