Inventory - Narrative (Details) $ in Thousands		3 Months Ended	9 Months Ended
	May 03, 2017 community lot	Jun. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Inventory Disclosure [Abstract]
Number of communities tested for impairment | community	17
Number of units in real estate property | lot	4,600
Net realizable value adjustments (NRV) - land held for sale		$ 81,006
Carrying amount impaired land - prior impairment				$ 151,000
Number of communities | community	2
Land inventory impairments		$ 31,487	$ 13,973	$ 131,254