Business Combinations - Summary of Business Acquisitions (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Cash paid			$ 38,825	$ 24,740
Seller Obligations			6,965	4,322
Total Purchase Price			45,790	29,062
Revenue	$ 420,486	$ 396,449	1,211,756	1,110,398
Net Income	28,077	21,212	$ 69,402	$ 48,965
Royals [Member]
Business Acquisition [Line Items]
Date			Feb. 29, 2020
Acquisition Type			Asset
Cash paid			$ 7,590
Seller Obligations			2,500
Total Purchase Price			10,090
Revenue	2,843		6,650
Net Income	279		$ 628
First State Insulation [Member]
Business Acquisition [Line Items]
Date				Mar. 18, 2019
Acquisition Type				Asset
Cash paid				$ 5,125
Seller Obligations				1,355
Total Purchase Price				6,480
Revenue		3,156		6,586
Net Income		174		$ 374
Other Acquisition [Member]
Business Acquisition [Line Items]
Acquisition Type			Asset	Asset
Cash paid			$ 5,035	$ 3,450
Seller Obligations			1,538	974
Total Purchase Price			6,573	4,424
Revenue	1,879	7,262	2,643	7,262
Net Income	(252)	591	(291)	$ 591
Expert Insulation [Member]
Business Acquisition [Line Items]
Date				Jun. 24, 2019
Acquisition Type				Asset
Cash paid				$ 16,165
Seller Obligations				1,993
Total Purchase Price				18,158
Revenue		3,147		3,339
Net Income		193		160
2020 Acquisitions [Member]
Business Acquisition [Line Items]
Revenue	9,630		14,201
Net Income	(90)		$ 220
2019 Acquisitions [Member]
Business Acquisition [Line Items]
Revenue		13,565		17,187
Net Income		$ 958		$ 1,125
Energy One [Member]
Business Acquisition [Line Items]
Date			Aug. 10, 2020
Acquisition Type			Asset
Cash paid			$ 13,200
Seller Obligations			1,591
Total Purchase Price			14,791
Revenue	2,853		2,853
Net Income	(202)		$ (202)
Storm Master [Member]
Business Acquisition [Line Items]
Date			Aug. 31, 2020
Acquisition Type			Asset
Cash paid			$ 13,000
Seller Obligations			1,336
Total Purchase Price			14,336
Revenue	2,055		2,055
Net Income	$ 85		$ 85