Segment Reporting - Reconciliation of Pretax Operating Income From Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Income before income taxes	$ 171,294	$ 126,018	$ 111,638	$ 48,562	$ 112,246	$ 62,806	$ 74,331	$ 55,606	$ 457,512	$ 304,989	$ 263,854
Homebuilding Segment
Segment Reporting Information [Line Items]
Income before income taxes									378,517	244,762	217,494
Homebuilding Segment | Corporate
Segment Reporting Information [Line Items]
Income before income taxes									(46,441)	(64,477)	(58,656)
Homebuilding Segment | West | Operating Segments
Segment Reporting Information [Line Items]
Income before income taxes									229,951	163,069	128,829
Homebuilding Segment | Mountain | Operating Segments
Segment Reporting Information [Line Items]
Income before income taxes									175,001	136,313	134,710
Homebuilding Segment | East | Operating Segments
Segment Reporting Information [Line Items]
Income before income taxes									20,006	9,857	12,611
Financial Services Segment
Segment Reporting Information [Line Items]
Income before income taxes									78,995	60,227	46,360
Financial Services Segment | Mortgage operations | Operating Segments
Segment Reporting Information [Line Items]
Income before income taxes									71,017	29,312	31,920
Financial Services Segment | Other | Operating Segments
Segment Reporting Information [Line Items]
Income before income taxes									$ 7,978	$ 30,915	$ 14,440