Business Combinations - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands							12 Months Ended
	Oct. 17, 2016	Apr. 12, 2016	Aug. 10, 2015	Jun. 01, 2015	Apr. 06, 2015	Mar. 12, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Intangibles							$ 30,300	$ 55,400
Goodwill							107,086	90,512	$ 53,393
Gain on bargain purchase								(1,116)
Less seller obligations							4,459	13,180	3,544
Alpine [Member]
Business Acquisition [Line Items]
Accounts receivable							3,959
Inventories							700
Property and equipment							656
Intangibles							12,800
Goodwill							6,642
Accounts payable and other current liabilities							(2,046)
Fair value of assets acquired							22,711
Less seller obligations		$ 1,600					1,560
Cash paid							21,151
Eastern Contractor Services [Member]
Business Acquisition [Line Items]
Cash								165
Accounts receivable								2,768
Inventories								335
Other current assets								109
Property and equipment								1,364
Intangibles								13,871
Goodwill								9,904
Other non-current assets								322
Accounts payable and other current liabilities								(1,681)
Long-term debt								(82)
Other long-term liabilities								(1)
Fair value of assets acquired								27,074
Total purchase price								27,074
Less seller obligations			$ 2,900					2,875
Cash paid								24,199
Other Acquisition [Member]
Business Acquisition [Line Items]
Accounts receivable							2,502	4,093
Inventories							1,183	720
Other current assets							29	32
Property and equipment							1,615	1,574
Intangibles							11,067	10,534
Goodwill							5,928	4,809
Other non-current assets							345	60
Accounts payable and other current liabilities							(1,617)	(2,220)
Deferred income tax liabilities								(825)
Fair value of assets acquired							21,052	18,777
Gain on bargain purchase								(1,116)
Total purchase price								17,661
Less seller obligations							2,299	1,621
Cash paid							18,753	16,040
Combined Business Acquisitions [Member]
Business Acquisition [Line Items]
Cash							2,181	926	53
Accounts receivable							9,554	14,264	4,666
Inventories							2,215	2,454	1,315
Other current assets							30	548	195
Property and equipment							2,937	4,867	1,576
Intangibles							30,267	55,365	7,111
Goodwill							16,918	37,104	4,065
Other non-current assets							461	4,118
Accounts payable and other current liabilities							(4,611)	(9,773)	(2,470)
Deferred income tax liabilities								(6,320)	(515)
Long-term debt								(82)
Other long-term liabilities								(3,975)	(35)
Fair value of assets acquired							59,952	99,496	15,961
Gain on bargain purchase								(1,116)
Total purchase price								98,380
Less seller obligations							4,459	13,180	3,544
Cash paid							55,493	85,200	$ 12,417
BDI Insulation [Member]
Business Acquisition [Line Items]
Cash								661
Accounts receivable								4,735
Inventories								980
Other current assets								368
Property and equipment								1,006
Intangibles								21,280
Goodwill								16,213
Other non-current assets								3,736
Accounts payable and other current liabilities								(3,303)
Deferred income tax liabilities								(5,495)
Other long-term liabilities								(3,736)
Fair value of assets acquired								36,445
Total purchase price								36,445
Less seller obligations						$ 5,800		5,765
Cash paid								30,680
CQ Insulation [Member]
Business Acquisition [Line Items]
Cash								100
Accounts receivable								1,423
Inventories								152
Other current assets								39
Property and equipment								190
Intangibles								4,350
Goodwill								3,035
Accounts payable and other current liabilities								(1,539)
Other long-term liabilities								(238)
Fair value of assets acquired								7,512
Total purchase price								7,512
Less seller obligations					$ 2,300			2,319
Cash paid								5,193
Layman Brothers Contracting [Member]
Business Acquisition [Line Items]
Accounts receivable								1,245
Inventories								267
Property and equipment								733
Intangibles								5,330
Goodwill								3,143
Accounts payable and other current liabilities								(1,030)
Fair value of assets acquired								9,688
Total purchase price								9,688
Less seller obligations				$ 600				600
Cash paid								$ 9,088
East Coast Insulators II, L.L.C [Member]
Business Acquisition [Line Items]
Cash							2,181
Accounts receivable							3,093
Inventories							332
Other current assets							1
Property and equipment							666
Intangibles							6,400
Goodwill							4,348
Other non-current assets							116
Accounts payable and other current liabilities							(948)
Fair value of assets acquired							16,189
Less seller obligations	$ 600						600
Cash paid							$ 15,589