Senior Notes, Secured, and Unsecured Indebtedness - Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Nov. 21, 2014	Aug. 11, 2014	Mar. 31, 2014	Nov. 08, 2012
ASSETS
Cash and cash equivalents	$ 40,710	$ 50,203	$ 26,379	$ 52,771
Restricted cash	0	504
Receivables	8,121	14,838
Escrow proceeds receivable	0	3,041
Real estate inventories	1,856,034	1,675,106
Investment in unconsolidated joint ventures	8,414	5,413
Goodwill	66,902	66,902
Intangibles, net	6,700	6,700
Deferred income taxes, net	79,728	79,726
Other assets, net	17,321	21,017
Investments in subsidiaries	0	0
Intercompany receivables	0	0
Total Assets	2,083,930	1,923,450
LIABILITIES AND EQUITY
Accounts payable	76,921	75,881
Accrued expenses	82,012	70,324
Notes payable	259,342	175,181
Total debt	1,185,684	1,105,776
Intercompany payables	0	0
Total liabilities	1,344,617	1,251,981
Equity
William Lyon Homes stockholders’ equity (deficit)	671,670	632,095
Noncontrolling interests	67,643	39,374
Total liabilities and equity	2,083,930	1,923,450
Subordinated amortizing notes
LIABILITIES AND EQUITY
Total debt	8,970	14,066
Equity
Stated interest rate					5.50%
5 3/4% Senior Notes due April 15, 2019
LIABILITIES AND EQUITY
Total debt	$ 148,691	$ 148,295
Equity
Stated interest rate	5.75%	5.75%
8 1/2% Senior Notes due November 15, 2020
LIABILITIES AND EQUITY
Total debt	$ 422,852	$ 422,896
Equity
Stated interest rate	8.50%	8.50%
7% Senior Notes due August 15, 2022
LIABILITIES AND EQUITY
Total debt	$ 345,829	$ 345,338
Equity
Stated interest rate	7.00%	7.00%
Reporting Entities | Delaware Lyon
ASSETS
Cash and cash equivalents	$ 0	$ 0	0	0
Restricted cash	0	0
Receivables	0	0
Escrow proceeds receivable	0	0
Real estate inventories	0	0
Investment in unconsolidated joint ventures	0	0
Goodwill	0	0
Intangibles, net	0	0
Deferred income taxes, net	0	0
Other assets, net	0	0
Investments in subsidiaries	671,670	632,095
Intercompany receivables	0	0
Total Assets	671,670	632,095
LIABILITIES AND EQUITY
Accounts payable	0	0
Accrued expenses	0	0
Notes payable	0	0
Intercompany payables	0	0
Total liabilities	0	0
Equity
William Lyon Homes stockholders’ equity (deficit)	671,670	632,095
Noncontrolling interests	0	0
Total liabilities and equity	671,670	632,095
Reporting Entities | Delaware Lyon | Subordinated amortizing notes
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Delaware Lyon | 5 3/4% Senior Notes due April 15, 2019
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Delaware Lyon | 8 1/2% Senior Notes due November 15, 2020
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Delaware Lyon | 7% Senior Notes due August 15, 2022
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | California Lyon
ASSETS
Cash and cash equivalents	35,703	44,332	18,896	48,462
Restricted cash	0	504
Receivables	3,083	8,986
Escrow proceeds receivable	0	2,020
Real estate inventories	957,404	922,990
Investment in unconsolidated joint ventures	8,264	5,263
Goodwill	14,209	14,209
Intangibles, net	0	0
Deferred income taxes, net	79,728	79,726
Other assets, net	15,804	18,980
Investments in subsidiaries	(25,323)	(34,522)
Intercompany receivables	0	0
Total Assets	1,088,872	1,062,488
LIABILITIES AND EQUITY
Accounts payable	54,287	45,065
Accrued expenses	75,808	62,167
Notes payable	133,126	80,915
Intercompany payables	176,227	170,757
Total liabilities	1,365,790	1,289,499
Equity
William Lyon Homes stockholders’ equity (deficit)	(276,917)	(227,011)
Noncontrolling interests	(1)	0
Total liabilities and equity	1,088,872	1,062,488
Reporting Entities | California Lyon | Subordinated amortizing notes
LIABILITIES AND EQUITY
Total debt	8,970	14,066
Reporting Entities | California Lyon | 5 3/4% Senior Notes due April 15, 2019
LIABILITIES AND EQUITY
Total debt	148,691	148,295
Reporting Entities | California Lyon | 8 1/2% Senior Notes due November 15, 2020
LIABILITIES AND EQUITY
Total debt	422,852	422,896
Reporting Entities | California Lyon | 7% Senior Notes due August 15, 2022
LIABILITIES AND EQUITY
Total debt	345,829	345,338
Reporting Entities | Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	528	2,723	927	573
Restricted cash	0	0
Receivables	1,757	937
Escrow proceeds receivable	0	1,021
Real estate inventories	662,342	589,762
Investment in unconsolidated joint ventures	150	150
Goodwill	52,693	52,693
Intangibles, net	6,700	6,700
Deferred income taxes, net	0	0
Other assets, net	1,197	1,738
Investments in subsidiaries	(608,347)	(561,546)
Intercompany receivables	248,639	239,248
Total Assets	365,659	333,426
LIABILITIES AND EQUITY
Accounts payable	16,343	27,807
Accrued expenses	6,098	8,059
Notes payable	2,979	0
Intercompany payables	0	0
Total liabilities	25,420	35,866
Equity
William Lyon Homes stockholders’ equity (deficit)	340,240	297,560
Noncontrolling interests	0	0
Total liabilities and equity	365,660	333,426
Reporting Entities | Guarantor Subsidiaries | Subordinated amortizing notes
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Guarantor Subsidiaries | 5 3/4% Senior Notes due April 15, 2019
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Guarantor Subsidiaries | 8 1/2% Senior Notes due November 15, 2020
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Guarantor Subsidiaries | 7% Senior Notes due August 15, 2022
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Non-Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	4,479	3,148	6,556	3,736
Restricted cash	0	0
Receivables	3,281	4,915
Escrow proceeds receivable	0	0
Real estate inventories	236,288	162,354
Investment in unconsolidated joint ventures	0	0
Goodwill	0	0
Intangibles, net	0	0
Deferred income taxes, net	0	0
Other assets, net	320	299
Investments in subsidiaries	0	0
Intercompany receivables	0	0
Total Assets	244,368	170,716
LIABILITIES AND EQUITY
Accounts payable	6,291	3,009
Accrued expenses	106	98
Notes payable	123,237	94,266
Intercompany payables	72,412	68,491
Total liabilities	202,046	165,864
Equity
William Lyon Homes stockholders’ equity (deficit)	(25,323)	(34,522)
Noncontrolling interests	67,644	39,374
Total liabilities and equity	244,367	170,716
Reporting Entities | Non-Guarantor Subsidiaries | Subordinated amortizing notes
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Non-Guarantor Subsidiaries | 5 3/4% Senior Notes due April 15, 2019
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Non-Guarantor Subsidiaries | 8 1/2% Senior Notes due November 15, 2020
LIABILITIES AND EQUITY
Total debt	0	0
Reporting Entities | Non-Guarantor Subsidiaries | 7% Senior Notes due August 15, 2022
LIABILITIES AND EQUITY
Total debt	0	0
Consolidation, Eliminations
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Restricted cash	0	0
Receivables	0	0
Escrow proceeds receivable	0	0
Real estate inventories	0	0
Investment in unconsolidated joint ventures	0	0
Goodwill	0	0
Intangibles, net	0	0
Deferred income taxes, net	0	0
Other assets, net	0	0
Investments in subsidiaries	(38,000)	(36,027)
Intercompany receivables	(248,639)	(239,248)
Total Assets	(286,639)	(275,275)
LIABILITIES AND EQUITY
Accounts payable	0	0
Accrued expenses	0	0
Notes payable	0	0
Intercompany payables	(248,639)	(239,248)
Total liabilities	(248,639)	(239,248)
Equity
William Lyon Homes stockholders’ equity (deficit)	(38,000)	(36,027)
Noncontrolling interests	0	0
Total liabilities and equity	(286,639)	(275,275)
Consolidation, Eliminations | Subordinated amortizing notes
LIABILITIES AND EQUITY
Total debt	0	0
Consolidation, Eliminations | 5 3/4% Senior Notes due April 15, 2019
LIABILITIES AND EQUITY
Total debt	0	0
Consolidation, Eliminations | 8 1/2% Senior Notes due November 15, 2020
LIABILITIES AND EQUITY
Total debt	0	0
Consolidation, Eliminations | 7% Senior Notes due August 15, 2022
LIABILITIES AND EQUITY
Total debt	0	0
Senior Notes
LIABILITIES AND EQUITY
Total debt	917,372	916,529
Senior Notes | 5 3/4% Senior Notes due April 15, 2019
LIABILITIES AND EQUITY
Total debt	$ 148,691	$ 148,295
Equity
Stated interest rate	5.75%	5.75%					5.75%
Senior Notes | 8 1/2% Senior Notes due November 15, 2020
LIABILITIES AND EQUITY
Total debt	$ 422,852	$ 422,896
Equity
Stated interest rate	8.50%	8.50%						8.50%
Senior Notes | 7% Senior Notes due August 15, 2022
LIABILITIES AND EQUITY
Total debt	$ 345,829	$ 345,338
Equity
Stated interest rate	7.00%	7.00%				7.00%