Consolidated Statements of Operations and Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues	$ 3,065,216,000	$ 2,577,614,000	$ 2,326,844,000
Inventory impairments	(21,850,000)	(10,010,000)	(10,173,000)
Net realized gains (losses) from the sales of marketable securities		18,122,000	1,074,000
Realized gain from the sale of metropolitan district bond securities (related party)		35,847,000
Other-than-temporary impairment of marketable securities	0	(300,000)	(1,400,000)
Pretax income	263,854,000	229,732,000	151,781,000
Provision for income taxes	(53,074,000)	(87,897,000)	(48,570,000)
Net income	210,780,000	141,835,000	103,211,000
Other comprehensive income (loss) related to available-for-sale securities, net of tax		(18,079,000)	6,356,000
Comprehensive income	$ 210,780,000	$ 123,756,000	$ 109,567,000
Earnings per share:
Basic (in dollars per share)	$ 3.74	$ 2.54	$ 1.86
Diluted (in dollars per share)	$ 3.66	$ 2.48	$ 1.85
Weighted average common shares outstanding
Basic (in shares)	56,084,373	55,663,908	55,389,898
Diluted (in shares)	57,250,704	56,901,461	55,562,920
Homebuilding Segment [Member]
Revenues	$ 2,981,811,000	$ 2,503,242,000	$ 2,262,853,000
Cost of sales	(2,436,989,000)	(2,088,283,000)	(1,899,430,000)
Inventory impairments	(21,850,000)	(10,010,000)	(10,173,000)
Gross margin	544,822,000	414,959,000	363,423,000
Selling, general and administrative expenses	(329,801,000)	(287,488,000)	(250,540,000)
Interest and other income	7,718,000	7,714,000	6,033,000
Net realized gains (losses) from the sales of marketable securities		17,775,000	979,000
Realized gain from the sale of metropolitan district bond securities (related party)		35,847,000
Other expense	(5,245,000)	(2,817,000)	(3,447,000)
Other-than-temporary impairment of marketable securities		(51,000)	(1,070,000)
Pretax income	217,494,000	185,939,000	115,378,000
Homebuilding Segment [Member] | Home Building [Member]
Revenues	2,981,811,000	2,498,695,000	2,257,153,000
Cost of sales	(2,415,139,000)	(2,073,833,000)	(1,884,391,000)
Homebuilding Segment [Member] | Land [Member]
Revenues		4,547,000	5,700,000
Cost of sales		(4,440,000)	(4,866,000)
Financial Services Segment [Member]
Revenues	83,405,000	74,372,000	63,991,000
Net realized gains (losses) from the sales of marketable securities	(3,745,000)
Other-than-temporary impairment of marketable securities		(235,000)	(373,000)
Pretax income	46,360,000	43,793,000	36,403,000
Expenses	(38,200,000)	(34,534,000)	(30,920,000)
Interest and other income	$ 4,900,000	$ 4,190,000	$ 3,705,000