Contingencies - Warranty (Details)	3 Months Ended		9 Months Ended	12 Months Ended		18 Months Ended
	Dec. 31, 2015 USD ($) home	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) home	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($) Community	Dec. 31, 2015 USD ($) home
Loss Contingencies [Line Items]
Standard product warranty length, minimum	1 year
Standard product warranty length, maximum	2 years
Limited product warranty length	5 years
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 27,681,000	$ 16,084,000		$ 16,084,000
Accruals for warranties issued (a)	2,615,000	1,525,000
Changes in liability related to warranties existing in prior periods	10,600,000	14,230,000
Payments made (b)	(11,983,000)	(4,612,000)
Balance at end of period	28,913,000	27,227,000	$ 28,913,000	27,681,000	$ 16,084,000	$ 28,913,000
Insurance Recoveries	16,500,000		35,400,000
InsuranceReceivableNet	13,700,000		13,700,000			13,700,000
Specific Warranty Issue
Movement in Standard Product Warranty Accrual [Roll Forward]
Product warranty expense						41,100,000
Specific Warranty Issue | FLORIDA
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	14,500,000
Balance at end of period	14,700,000		$ 14,700,000	14,500,000		14,700,000
Product warranty expense	$ 9,000,000	$ 13,600,000		$ 26,300,000	4,300,000	$ 39,600,000
Homes likely to require more than minor repairs | home	1,000		1,000			1,000
Movement on Number of Homes Likely to be Repaired | home	67
Homes Have Been Repaired | home	0		0			0
Product warranty accrual, payments	$ (8,800,000)
Excess Insurance Recovery	3,600,000
Specific Warranty Issue | NEW JERSEY
Movement in Standard Product Warranty Accrual [Roll Forward]
Product warranty expense	$ 900,000				$ 600,000	$ 1,500,000
Number of Communities With Water Intrusion Issues	2				1