Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest expense	$ (6,329)	$ (5,914)	$ (12,611)	$ (11,750)
Income before taxes	241,586	208,968	432,584	341,129
Income tax expense	(38,412)	(61,091)	(63,361)	(90,329)
Net income	$ 203,174	$ 147,877	$ 369,223	$ 250,800
Basic earnings per share (USD per share)	$ 55.90	$ 39.46	$ 101.03	$ 67.30
Diluted earnings per share (USD per share)	$ 49.05	$ 35.19	$ 88.31	$ 60.36
Basic weighted average shares outstanding (in shares)	3,635	3,748	3,655	3,726
Diluted weighted average shares outstanding (in shares)	4,142	4,202	4,181	4,155
Homebuilding [Member]
Revenues	$ 1,750,463	$ 1,512,714	$ 3,240,556	$ 2,760,301
Other income	2,164	1,447	4,141	2,549
Cost of sales	(1,416,797)	(1,218,083)	(2,628,743)	(2,244,100)
Selling, general and administrative	(106,517)	(99,100)	(212,064)	(199,004)
Operating income	229,313	196,978	403,890	319,746
Interest expense	(6,047)	(5,641)	(12,054)	(11,219)
Income before taxes	223,266	191,337	391,836	308,527
Mortgage Banking [Member]
Mortgage banking fees	36,842	31,778	76,163	61,283
Interest income	2,915	1,554	5,008	3,215
Other income	641	506	1,165	815
General and administrative	(21,796)	(15,934)	(41,031)	(32,180)
Interest expense	(282)	(273)	(557)	(531)
Income before taxes	$ 18,320	$ 17,631	$ 40,748	$ 32,602