Business Combinations - Summary of Fair Value of Assets Acquired and Liabilities Created (Detail) (Details) $ in Thousands	Jan. 08, 2016 USD ($)	Jul. 21, 2015 USD ($) division	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Apr. 30, 2015 USD ($)
Assets Acquired
Goodwill			$ 66,198	$ 57,698
East [Member]
Assets Acquired
Goodwill				27,800
West [Member]
Assets Acquired
Goodwill				6,500
Acadia Homes [Member]
Business Acquisition [Line Items]
Purchase price	$ 83,600
Seller financing and holdbacks, and contingent consideration included in purchase price	19,700
Assets Acquired
Real estate inventory	76,152
Land deposits	984
Prepaid expenses and other assets	816
Property and equipment	204
Goodwill	8,500
Total assets	86,656
Less Liabilities Assumed
Accrued expenses and other liabilities	2,562
Customer deposits	463
Net assets acquired	$ 83,631
JEH Homes [Member]
Assets Acquired
Real estate inventory					$ 55,559
Land deposits					0
Prepaid expenses and other assets					1,301
Property and equipment					395
Goodwill					9,125
Total assets					66,380
Less Liabilities Assumed
Accrued expenses and other liabilities					0
Customer deposits					0
Net assets acquired					$ 66,380
Orleans Homes [Member]
Business Acquisition [Line Items]
Number of divisions acquired (in division) | division		3
Assets Acquired
Real estate inventory		$ 140,602
Land deposits		2,236
Prepaid expenses and other assets		2,436
Property and equipment		623
Goodwill		25,198
Total assets		171,095
Less Liabilities Assumed
Accrued expenses and other liabilities		2,700
Customer deposits		1,081
Net assets acquired		$ 167,314
Total Prior Year Acquisitions [Member]
Assets Acquired
Real estate inventory				196,161
Land deposits				2,236
Prepaid expenses and other assets				3,737
Property and equipment				1,018
Goodwill				34,323
Total assets				237,475
Less Liabilities Assumed
Accrued expenses and other liabilities				2,700
Customer deposits				1,081
Net assets acquired				$ 233,694