Results of Quarterly Operations (Schedule Of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues									$ 2,147,413	$ 1,423,799	$ 994,440
Income before income tax expense	$ 36,062	$ 22,859	$ 46,502	$ 23,107	$ 33,848	$ 15,156	$ 23,109	$ 12,051	128,530	84,164	73,149
Net income	$ 26,195	$ 17,048	$ 33,193	$ 20,019	$ 17,195	$ 9,470	$ 14,831	$ 8,799	$ 96,455	$ 50,295	$ 49,540
Basic earnings per share	$ 0.85	$ 0.56	$ 1.11	$ 0.68	$ 0.61	$ 0.37	$ 0.67	$ 0.40	$ 3.20	$ 2.06	$ 2.34
Diluted earnings per share	$ 0.85	$ 0.56	$ 1.10	$ 0.67	$ 0.60	$ 0.37	$ 0.66	$ 0.40	$ 3.17	$ 2.03	$ 2.33
Home Sales [Member]
Revenues	$ 640,187	$ 552,876	$ 522,164	$ 394,831	$ 516,500	$ 374,935	$ 287,588	$ 226,420	$ 2,110,058	$ 1,405,443	$ 978,733
Gross margin from home sales revenues	$ 105,492	$ 92,732	$ 94,967	$ 75,248	$ 90,718	$ 63,570	$ 53,700	$ 44,096