Business Segments Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenue	$ 722,485	$ 567,842	$ 558,098	$ 437,857	$ 621,702	$ 476,423	$ 456,866	$ 406,980	$ 2,286,282	$ 1,961,971	$ 1,691,327
Operating income (loss):									163,161	138,659	108,743
Interest									20,484	18,874	17,598
Equity in income from joint venture arrangements									(312)	(539)	(640)
Acquisition and integration costs									1,700	0	0
Income before income taxes									141,289	120,324	91,785
Depreciation and amortization:									14,531	14,174	13,606
Midwest Homebuilding [Member]
Segment Reporting Information [Line Items]
Revenue									933,119	742,577	637,894
Operating income (loss):									86,131	81,522	70,446
Interest									7,142	5,010	3,754
Depreciation and amortization:									2,448	2,069	1,752
Southern Homebuilding [Member]
Segment Reporting Information [Line Items]
Revenue									925,404	730,482	602,273
Operating income (loss):									72,600	36,798	20,398
Interest									7,362	8,508	8,039
Depreciation and amortization:									3,210	3,014	2,525
Mid-Atlantic Homebuilding [Member]
Segment Reporting Information [Line Items]
Revenue									375,563	439,219	409,149
Operating income (loss):									23,312	35,598	33,450
Interest									2,711	2,599	3,693
Depreciation and amortization:									1,262	1,565	1,645
Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue									52,196	49,693	42,011
Operating income (loss):									27,482	27,288	23,262
Interest									3,269	2,757	2,112
Depreciation and amortization:									1,281	1,503	1,948
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Less: Corporate selling, general and administrative expenses									(46,364)	(42,547)	(38,813)
Depreciation and amortization:									$ 6,330	$ 6,023	$ 5,736