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Segment Information, Nature of Operations, and Certain Concentrations - Additional Information (Detail) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 Trade_Names metropolitan_area segment | Sep. 10, 2012
Segment Reporting Information [Line Items] |  |
Number of trade names | Trade_Names | 3 |
Number of metropolitan areas Ryan Homes product are sold | metropolitan_area | 29 |
Senior Notes due 2022 |  |
Segment Reporting Information [Line Items] |  |
Senior notes interest rate | 3.95% | 3.95%
Homebuilding: |  |
Segment Reporting Information [Line Items] |  |
Number of reportable segments | 4 |
Mortgage Banking: |  |
Segment Reporting Information [Line Items] |  |
Number of reportable segments | 1 |
Geographic Concentration Risk | Homebuilding: | District of Columbia |  |
Segment Reporting Information [Line Items] |  |
Revenue derived | 30.00% |
Geographic Concentration Risk | Homebuilding: | Maryland, Baltimore |  |
Segment Reporting Information [Line Items] |  |
Revenue derived | 11.00% |

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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611 + Details
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