Segment Information (Land-Related Charges By Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information
Total land-related charges	$ 191,912	$ 19,336	$ 11,467
Northeast [Member]
Segment Reporting Information
Total land-related charges	51,362	2,079	3,301
Southeast [Member]
Segment Reporting Information
Total land-related charges	55,689	3,089	3,022
Florida [Member]
Segment Reporting Information
Total land-related charges	9,702	715	4,555
Texas [Member]
Segment Reporting Information
Total land-related charges	2,521	515	295
Midwest [Member]
Segment Reporting Information
Total land-related charges	8,917	3,383	2,319
West [Member]
Segment Reporting Information
Total land-related charges	56,995	8,960	(2,615)
Other Homebuilding [Member]
Segment Reporting Information
Total land-related charges	$ 6,726	$ 595	$ 590