Business Segments Business Segments (Details) $ in Thousands	3 Months Ended						12 Months Ended
	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments							15
Revenue							$ 1,961,971	$ 1,691,327	$ 1,418,395
Operating income (loss):							138,659	108,743	111,794
Interest							18,874	17,598	17,521
Equity in income of joint venture arrangements							(539)	(640)	(498)
Loss on early extinguishment of debt							0	0	7,842
Income before income taxes							120,324	91,785	86,929
Depreciation and amortization:							14,174	13,606	10,928
Standard and Extended Product Warranty Accrual, Period Increase (Decrease)		$ 8,500		$ 14,500	$ 2,800	$ 2,200	8,500	19,409	0
Total valuation adjustments and write-offs	$ 7,681		$ 3,992						3,638
Midwest Homebuilding [Member]
Segment Reporting Information [Line Items]
Homebuilding revenue							742,577	637,894	500,873
Operating income (loss):							81,522	70,446	51,436
Interest							5,010	3,754	4,005
Depreciation and amortization:							2,069	1,752	1,614
Southern Homebuilding [Member]
Segment Reporting Information [Line Items]
Homebuilding revenue							730,482	602,273	514,747
Operating income (loss):							36,798	20,398	47,276
Interest							8,508	8,039	7,244
Depreciation and amortization:							3,014	2,525	2,069
Mid-Atlantic Homebuilding [Member]
Segment Reporting Information [Line Items]
Homebuilding revenue							439,219	409,149	366,800
Operating income (loss):							35,598	33,450	25,144
Interest							2,599	3,693	4,656
Depreciation and amortization:							1,565	1,645	1,464
Financial Services [Member]
Segment Reporting Information [Line Items]
Financial services revenue							49,693	42,011	35,975
Operating income (loss):							27,288	23,262	21,032
Interest							2,757	2,112	1,616
Depreciation and amortization:							1,503	1,948	1,213
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Less: Corporate selling, general and administrative expenses							(42,547)	(38,813)	(33,094)
Depreciation and amortization:							$ 6,023	$ 5,736	$ 4,568