Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues	$ 1,852,407	$ 1,667,920	$ 5,169,126	$ 4,489,504
Interest expense	(6,197)	(6,120)	(18,808)	(17,870)
Income before taxes	249,710	244,464	682,294	585,593
Income tax expense	(53,894)	(82,362)	(117,255)	(172,691)
Net income	$ 195,816	$ 162,102	$ 565,039	$ 412,902
Basic earnings per share (USD per share)	$ 54.21	$ 43.26	$ 155.22	$ 110.60
Diluted earnings per share (USD per share)	$ 48.28	$ 38.02	$ 136.53	$ 98.33
Basic weighted average shares outstanding (in shares)	3,612	3,747	3,640	3,733
Diluted weighted average shares outstanding (in shares)	4,056	4,263	4,139	4,199
Home Building [Member]
Revenues	$ 1,809,345	$ 1,633,726	$ 5,049,901	$ 4,394,027
Other income	2,840	1,715	6,981	4,264
Cost of Goods and Services Sold	1,472,649	1,307,971	4,101,392	3,552,071
Selling, general and administrative	(109,372)	(95,606)	(321,436)	(294,610)
Operating income	230,164	231,864	634,054	551,610
Interest expense	(5,968)	(5,821)	(18,022)	(17,040)
Income before taxes	224,196	226,043	616,032	534,570
Mortgage Banking [Member]
Revenues	43,062	34,194	119,225	95,477
Interest income	3,362	1,953	8,370	5,168
Other income	659	583	1,824	1,398
General and administrative	(21,340)	(18,010)	(62,371)	(50,190)
Interest expense	(229)	(299)	(786)	(830)
Income before taxes	$ 25,514	$ 18,421	$ 66,262	$ 51,023