Note 6 - Accumulated Other Comprehensive Income - Reclassifications Out of AOCI (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Homebuilding: Net realized gains (losses) from the sales of marketable securities										$ 18,122,000	$ 1,074,000
Homebuilding: 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)
Income before income taxes	$ 69,286,000	$ 67,420,000	$ 76,616,000	$ 50,532,000	$ 51,798,000	$ 89,680,000	$ 51,894,000	$ 36,360,000	263,854,000	229,732,000	151,781,000
Provision for income taxes									(53,074,000)	(87,897,000)	(48,570,000)
Net income	$ 54,725,000	$ 53,392,000	$ 63,899,000	$ 38,764,000	$ 24,552,000	$ 61,163,000	$ 33,871,000	$ 22,249,000	210,780,000	141,835,000	103,211,000
Homebuilding Segment [Member]
Homebuilding: Net realized gains (losses) from the sales of marketable securities										17,775,000	979,000
Homebuilding: Realized gain from the sale of metropolitan district bond securities (related party)										35,847,000
Other-than-temporary impairment of marketable securities										(51,000)	(1,070,000)
Income before income taxes									217,494,000	185,939,000	115,378,000
Financial Services Segment [Member]
Homebuilding: Net realized gains (losses) from the sales of marketable securities									(3,745,000)
Other-than-temporary impairment of marketable securities										(235,000)	(373,000)
Interest and other income									4,900,000	4,190,000	3,705,000
Income before income taxes									46,360,000	43,793,000	36,403,000
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Income before income taxes										53,683,000	(369,000)
Provision for income taxes										(20,400,000)	140,000
Net income										33,283,000	(229,000)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Homebuilding Segment [Member]
Homebuilding: Net realized gains (losses) from the sales of marketable securities										17,775,000	979,000
Homebuilding: Realized gain from the sale of metropolitan district bond securities (related party)										35,847,000
Other-than-temporary impairment of marketable securities										(51,000)	(1,070,000)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Financial Services Segment [Member]
Other-than-temporary impairment of marketable securities										(235,000)	(373,000)
Interest and other income										$ 347,000	$ 95,000