Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest expense	$ (6,282)	$ (5,836)
Income before taxes	190,998	132,161
Income tax expense	(24,949)	(29,238)
Net income	$ 166,049	$ 102,923
Basic earnings per share (USD per share)	$ 45.19	$ 27.78
Diluted earnings per share (USD per share)	$ 39.34	$ 25.12
Basic weighted average shares outstanding (in shares)	3,675	3,705
Diluted weighted average shares outstanding (in shares)	4,220	4,097
Homebuilding [Member]
Revenues	$ 1,490,093	$ 1,247,587
Other income	1,977	1,102
Cost of sales	(1,211,946)	(1,026,017)
Selling, general and administrative	(105,547)	(99,904)
Operating income	174,577	122,768
Interest expense	(6,007)	(5,578)
Income before taxes	168,570	117,190
Mortgage Banking [Member]
Mortgage banking fees	39,321	29,505
Interest income	2,093	1,661
Other income	524	309
General and administrative	(19,235)	(16,246)
Interest expense	(275)	(258)
Income before taxes	$ 22,428	$ 14,971