Inventories - Inventory Impairments (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2021	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Inventory [Line Items]
Inventory Impairments	$ 1,600	$ 325	$ 610	$ 1,600	$ 0	$ 935
Homebuilding Segment
Inventory [Line Items]
Inventory Impairments				1,600	0	935
Homebuilding Segment | Housing completed or under construction
Inventory [Line Items]
Inventory Impairments				1,600	0	535
Homebuilding Segment | Land and land under development
Inventory [Line Items]
Inventory Impairments				0	0	400
Homebuilding Segment | West | Housing completed or under construction
Inventory [Line Items]
Inventory Impairments				1,600	0	100
Homebuilding Segment | West | Land and land under development
Inventory [Line Items]
Inventory Impairments				0	0	0
Homebuilding Segment | Mountain | Housing completed or under construction
Inventory [Line Items]
Inventory Impairments				0	0	0
Homebuilding Segment | Mountain | Land and land under development
Inventory [Line Items]
Inventory Impairments				0	0	400
Homebuilding Segment | East | Housing completed or under construction
Inventory [Line Items]
Inventory Impairments				0	0	435
Homebuilding Segment | East | Land and land under development
Inventory [Line Items]
Inventory Impairments				$ 0	$ 0	$ 0