Results of Quarterly Operations (Schedule Of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues									$ 3,161,192	$ 2,535,911	$ 2,147,413
Income before income tax expense	$ 121,164	$ 64,885	$ 50,103	$ 34,088	$ 53,968	$ 34,840	$ 20,830	$ 22,997	270,240	132,635	128,530
Net income	$ 91,817	$ 49,764	$ 38,450	$ 26,126	$ 53,358	$ 27,024	$ 15,495	$ 17,117	$ 206,157	$ 112,994	$ 96,455
Basic earnings per share	$ 2.75	$ 1.49	$ 1.15	$ 0.79	$ 1.65	$ 0.88	$ 0.51	$ 0.57	$ 6.19	$ 3.66	$ 3.20
Diluted earnings per share	$ 2.72	$ 1.48	$ 1.15	$ 0.78	$ 1.63	$ 0.87	$ 0.51	$ 0.56	$ 6.13	$ 3.62	$ 3.17
Home Sales [Member]
Revenues	$ 946,803	$ 760,239	$ 747,415	$ 572,710	$ 775,667	$ 573,860	$ 608,636	$ 523,302	$ 3,027,167	$ 2,481,465	$ 2,110,058
Gross margin from home sales revenues	$ 197,216	$ 132,875	$ 126,760	$ 102,183	$ 142,945	$ 104,026	$ 104,708	$ 89,545