Note 21 - Supplemental Guarantor Information - Condensed Consolidating Statements of Cash Flows (Details) - USD ($)	1 Months Ended	9 Months Ended
	Apr. 30, 2017	Sep. 30, 2017	Sep. 30, 2016
Net cash provided by (used in) operating activities		$ (123,475,000)	$ 167,662,000
Investments in unconsolidated homebuilding joint ventures		(33,212,000)	(27,000,000)
Distributions of capital from unconsolidated homebuilding joint ventures		12,770,000	23,727,000
Net cash paid for acquisitions		(44,477,000)
Loan to parent and subsidiaries
Other investing activities		(11,113,000)	(5,389,000)
Net cash provided by (used in) investing activities		(76,032,000)	(8,662,000)
Change in restricted cash		(794,000)	7,309,000
Borrowings from revolving credit facility		685,550,000	1,008,000,000
Principal payments on revolving credit facility		(389,950,000)	(862,000,000)
Principal payments on secured project debt and other notes payable		(909,000)	(10,389,000)
Principal payment on senior notes payable		(483,000,000)	(280,000,000)
Proceeds from the issuance of senior notes payable	$ 225,000,000	579,125,000	300,000,000
Payment of debt issuance costs		(5,019,000)	(2,657,000)
Loan from subsidiary
Net proceeds from (payments on) mortgage credit facility		(94,641,000)	(141,524,000)
(Contributions to) distributions from Corporate and subsidiaries
Repurchases of common stock		(150,014,000)	(137,464,000)
Common stock dividend payments		(13,427,000)	(14,264,000)
Issuance of common stock under employee stock plans, net of tax withholdings		(5,807,000)	1,868,000
Other financing activities		(67,000)	(199,000)
Intercompany advances, net
Net cash provided by (used in) financing activities		121,047,000	(131,320,000)
Net increase (decrease) in cash and equivalents		(78,460,000)	27,680,000
Cash and equivalents at beginning of period		208,127,000	186,594,000
Cash and equivalents at end of period		129,667,000	214,274,000
Reportable Legal Entities [Member] | Parent Company [Member]
Net cash provided by (used in) operating activities		(287,435,000)	(49,169,000)
Investments in unconsolidated homebuilding joint ventures		(178,000)	(235,000)
Distributions of capital from unconsolidated homebuilding joint ventures		500,000	1,107,000
Net cash paid for acquisitions
Loan to parent and subsidiaries
Other investing activities		(2,098,000)	(325,000)
Net cash provided by (used in) investing activities		(1,776,000)	547,000
Change in restricted cash
Borrowings from revolving credit facility		685,550,000	1,008,000,000
Principal payments on revolving credit facility		(389,950,000)	(862,000,000)
Principal payments on secured project debt and other notes payable			(9,985,000)
Principal payment on senior notes payable		(483,000,000)	(280,000,000)
Proceeds from the issuance of senior notes payable		579,125,000	300,000,000
Payment of debt issuance costs		(5,019,000)	(2,657,000)
Loan from subsidiary		65,054,000	88,800,000
Net proceeds from (payments on) mortgage credit facility
(Contributions to) distributions from Corporate and subsidiaries		1,210,000	18,350,000
Repurchases of common stock		(150,014,000)	(137,464,000)
Common stock dividend payments		(13,427,000)	(14,264,000)
Issuance of common stock under employee stock plans, net of tax withholdings		(5,807,000)	1,868,000
Other financing activities
Intercompany advances, net		(74,078,000)	49,757,000
Net cash provided by (used in) financing activities		209,644,000	160,405,000
Net increase (decrease) in cash and equivalents		(79,567,000)	111,783,000
Cash and equivalents at beginning of period		105,261,000	6,387,000
Cash and equivalents at end of period		25,694,000	118,170,000
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities		16,744,000	16,087,000
Investments in unconsolidated homebuilding joint ventures		(79,000)	(192,000)
Distributions of capital from unconsolidated homebuilding joint ventures		1,867,000	333,000
Net cash paid for acquisitions
Loan to parent and subsidiaries
Other investing activities		(1,519,000)	(1,958,000)
Net cash provided by (used in) investing activities		269,000	(1,817,000)
Change in restricted cash
Borrowings from revolving credit facility
Principal payments on revolving credit facility
Principal payments on secured project debt and other notes payable
Principal payment on senior notes payable
Proceeds from the issuance of senior notes payable
Payment of debt issuance costs
Loan from subsidiary
Net proceeds from (payments on) mortgage credit facility
(Contributions to) distributions from Corporate and subsidiaries
Repurchases of common stock
Common stock dividend payments
Issuance of common stock under employee stock plans, net of tax withholdings
Other financing activities			(199,000)
Intercompany advances, net		(23,759,000)	(95,992,000)
Net cash provided by (used in) financing activities		(23,759,000)	(96,191,000)
Net increase (decrease) in cash and equivalents		(6,746,000)	(81,921,000)
Cash and equivalents at beginning of period		38,211,000	112,852,000
Cash and equivalents at end of period		31,465,000	30,931,000
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities		147,216,000	200,744,000
Investments in unconsolidated homebuilding joint ventures		(32,955,000)	(26,573,000)
Distributions of capital from unconsolidated homebuilding joint ventures		10,403,000	22,287,000
Net cash paid for acquisitions		(44,477,000)
Loan to parent and subsidiaries		(65,054,000)	(88,800,000)
Other investing activities		(7,496,000)	(3,106,000)
Net cash provided by (used in) investing activities		(139,579,000)	(96,192,000)
Change in restricted cash		(794,000)	7,309,000
Borrowings from revolving credit facility
Principal payments on revolving credit facility
Principal payments on secured project debt and other notes payable		(909,000)	(404,000)
Principal payment on senior notes payable
Proceeds from the issuance of senior notes payable
Payment of debt issuance costs
Loan from subsidiary
Net proceeds from (payments on) mortgage credit facility		(94,641,000)	(141,524,000)
(Contributions to) distributions from Corporate and subsidiaries		(1,210,000)	(18,350,000)
Repurchases of common stock
Common stock dividend payments
Issuance of common stock under employee stock plans, net of tax withholdings
Other financing activities		(67,000)
Intercompany advances, net		97,837,000	46,235,000
Net cash provided by (used in) financing activities		216,000	(106,734,000)
Net increase (decrease) in cash and equivalents		7,853,000	(2,182,000)
Cash and equivalents at beginning of period		64,655,000	67,355,000
Cash and equivalents at end of period		72,508,000	65,173,000
Consolidation, Eliminations [Member]
Net cash provided by (used in) operating activities
Investments in unconsolidated homebuilding joint ventures
Distributions of capital from unconsolidated homebuilding joint ventures
Net cash paid for acquisitions
Loan to parent and subsidiaries		65,054,000	88,800,000
Other investing activities
Net cash provided by (used in) investing activities		65,054,000	88,800,000
Change in restricted cash
Borrowings from revolving credit facility
Principal payments on revolving credit facility
Principal payments on secured project debt and other notes payable
Principal payment on senior notes payable
Proceeds from the issuance of senior notes payable
Payment of debt issuance costs
Loan from subsidiary		(65,054,000)	(88,800,000)
Net proceeds from (payments on) mortgage credit facility
(Contributions to) distributions from Corporate and subsidiaries
Repurchases of common stock
Common stock dividend payments
Issuance of common stock under employee stock plans, net of tax withholdings
Other financing activities
Intercompany advances, net
Net cash provided by (used in) financing activities		(65,054,000)	(88,800,000)
Net increase (decrease) in cash and equivalents
Cash and equivalents at beginning of period
Cash and equivalents at end of period