Segment Information - Details of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 231,502			$ 194,551			$ 652,545	$ 580,575
Net income	42,710	$ 47,218	$ 42,402	41,976	$ 35,710	$ 31,555	132,331	109,241
Depreciation and amortization							12,450	10,477
Income tax expense	14,435			13,790			43,938	33,520
Total Assets	718,235						718,235		$ 592,239
Residential [Member]
Segment Reporting Information [Line Items]
Net sales	218,435			182,775			614,187	541,722
Commercial [Member]
Segment Reporting Information [Line Items]
Net sales	13,067			11,776			38,358	38,853
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	231,502			194,551			652,545	580,575
Net income	42,710			41,976			132,331	109,241
EBITDA	61,472			58,609			187,918	152,340
Depreciation and amortization	4,535			3,587			12,450	10,380
Income tax expense	14,435			13,790			43,938	33,520
Capital expenditures	37,084			17,865			99,696	36,926
Total Assets	718,235			570,770			718,235	570,770
Operating Segments [Member] | Residential [Member]
Segment Reporting Information [Line Items]
Net sales	218,435			182,775			614,187	541,722
Net income	42,225			41,381			129,157	107,859
EBITDA	60,619			57,639			183,064	150,058
Depreciation and amortization	4,326			3,422			11,855	9,947
Income tax expense	14,276			13,580			42,853	33,046
Capital expenditures	36,887			17,766			98,913	35,584
Total Assets	624,904			482,825			624,904	482,825
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net sales	13,067			11,776			38,358	38,853
Net income	485			595			3,174	1,382
EBITDA	853			970			4,854	2,282
Depreciation and amortization	209			165			595	433
Income tax expense	159			210			1,085	474
Capital expenditures	197			99			783	1,342
Total Assets	$ 93,331			$ 87,945			$ 93,331	$ 87,945