Segment Information Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information
Home sale revenues	$ 8,323,984	$ 7,451,315	$ 5,792,675
Number of reportable segments | segment	6
Detached single-family homes [Member]
Segment Reporting Information
Home sale revenues	$ 7,300,000	6,500,000	5,000,000
Attached homes [Member]
Segment Reporting Information
Home sale revenues	$ 1,068,000	$ 996,400	$ 841,500