Business Combinations - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended								12 Months Ended			0 Months Ended
	Feb. 10, 2014	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 Business	Dec. 31, 2013 Business	Dec. 31, 2012 Business	Aug. 31, 2012	Nov. 16, 2012	Aug. 11, 2014	Mar. 24, 2014	Mar. 16, 2013	Nov. 01, 2013
Business Acquisition [Line Items]
Business combinations										3	2	2
Purchase price paid in cash										$ 12,364	$ 1,181	$ 823
Note payable issued in connection with acquisition of business										3,544	300	571
Revenue		145,270	140,456	126,348	105,946	119,330	115,951	104,686	91,962	518,020	431,929	301,253
Net income		5,056	6,196	2,307	373	2,377	2,967	1,226	(530)	13,932	6,040	(1,906)
Common stock issued for acquisition of business												4,100
Stock split ratio	19.5
Amortization expense of intangible assets										2,837	3,057	3,082
2014 Acquisitions [Member]
Business Acquisition [Line Items]
Purchase price paid in cash										12,417
Note payable issued in connection with acquisition of business										3,544
Revenue										13,492
Net income										938
Marv's Insulation [Member]
Business Acquisition [Line Items]
Ownership percentage acquired															100.00%
U.S. Insulation [Member]
Business Acquisition [Line Items]
Ownership percentage acquired																100.00%
2013 Acquisitions [Member]
Business Acquisition [Line Items]
Purchase price paid in cash										1,181
Note payable issued in connection with acquisition of business										380
Ace [Member]
Business Acquisition [Line Items]
Ownership percentage acquired																	100.00%
KMB [Member]
Business Acquisition [Line Items]
Ownership percentage acquired																		100.00%
Combined Business Acquisitions [Member]
Business Acquisition [Line Items]
Note payable issued in connection with acquisition of business										3,544	380	651
Common stock issued for acquisition of business												4,100
Amortization expense of intangible assets										435	614	567
TCI Contracting, LLC [Member]
Business Acquisition [Line Items]
Note payable issued in connection with acquisition of business													571
Ownership percentage acquired													100.00%
Issued and outstanding capital stock													87.50%
Percentage of common stock acquired													11.50%
Stock issued in stock split													2,533,908
Common stock issued for acquisition of business													4,100
Stock split ratio													19.5
TCI Contracting, LLC [Member] | Remaining Ownership Percentage [Member]
Business Acquisition [Line Items]
Issued and outstanding capital stock													12.50%
Accurate Building Products Inc [Member]
Business Acquisition [Line Items]
Purchase price paid in cash														1,198
Note payable issued in connection with acquisition of business														80
Ownership percentage acquired														100.00%
Revenue												14,097
Net income												$ 1,018