Results of Quarterly Operations (Schedule Of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues									$ 2,535,911	$ 2,147,413	$ 1,423,799
Income before tax expense	$ 53,968	$ 34,840	$ 20,830	$ 22,997	$ 36,062	$ 22,859	$ 46,502	$ 23,107	132,635	128,530	84,164
Net income	$ 53,358	$ 27,024	$ 15,495	$ 17,117	$ 26,195	$ 17,048	$ 33,193	$ 20,019	$ 112,994	$ 96,455	$ 50,295
Basic earnings per share	$ 1.65	$ 0.88	$ 0.51	$ 0.57	$ 0.85	$ 0.56	$ 1.11	$ 0.68	$ 3.66	$ 3.20	$ 2.06
Diluted earnings per share	$ 1.63	$ 0.87	$ 0.51	$ 0.56	$ 0.85	$ 0.56	$ 1.10	$ 0.67	$ 3.62	$ 3.17	$ 2.03
Home Sales [Member]
Revenues	$ 775,667	$ 573,860	$ 608,636	$ 523,302	$ 640,187	$ 552,876	$ 522,164	$ 394,831	$ 2,481,465	$ 2,110,058	$ 1,405,443
Gross margin from home sales revenues	$ 142,945	$ 104,026	$ 104,708	$ 89,545	$ 105,492	$ 92,732	$ 94,967	$ 75,248