Business Acquisitions - Summary of Final Purchase Price Attributable to Acquisitions (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Cash		$ 2,453	[1]	$ 1,119	$ 3,753
Accounts receivable and contract assets		19,174	[1]	7,846	11,788
Other current assets		2,185	[1]	572	404
Current assets		23,812	[1]	9,537	15,945
Property and equipment		3,936	[1]	183	1,713
Operating lease right-of-use asset—net		4,825	[1]	3,110	3,079
Other intangible assets	[1]	444
Goodwill		40,786	[1]	12,384	36,705
Total assets		98,846	[1]	39,401	95,542
Current liabilities		11,557	[1]	3,034	6,077
Operating lease liability—net of current portion		10,357	[1]	2,438	2,389
Deferred tax liability	[1]	1,999
Other non-current liabilities	[1]	130
Total liabilities		24,043	[1]	5,472	8,466
Purchase price		74,803	[1]	33,929	87,076
Customer Relationships
Business Acquisition [Line Items]
Intangible assets		19,962	[1]	11,619	31,623
Trade Names
Business Acquisition [Line Items]
Intangible assets		2,373	[1]	1,649	3,475
Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets		2,708	[1]	919	2,681
Acquired Technology
Business Acquisition [Line Items]
Intangible assets					321
Matrix
Business Acquisition [Line Items]
Cash		1,524		1,524
Accounts receivable and contract assets		15,752		15,752
Other current assets		1,832		2,094
Current assets		19,108		19,370
Property and equipment		2,231		2,231
Operating lease right-of-use asset—net		4,779		14,760
Goodwill		27,284		36,118
Total assets		70,532		72,479
Current liabilities		10,599		11,267
Operating lease liability—net of current portion		10,325		12,500
Deferred tax liability		896
Other non-current liabilities		130		130
Total liabilities		21,950		23,897
Purchase price		48,582		48,582
Measurement Period Adjustments
Cash		1,524
Other current assets		(262)
Current assets		1,262
Operating lease right-of-use asset		(9,981)
Goodwill		(8,834)
Total assets		(423)
Current liabilities		(668)
Operating lease liability-net of current portion		(2,175)
Deferred tax liability		896
Total liabilities		(1,947)
Purchase price		1,524
Matrix | Customer Relationships
Business Acquisition [Line Items]
Intangible assets		12,781
Measurement Period Adjustments
Intangible assets		12,781
Matrix | Trade Names
Business Acquisition [Line Items]
Intangible assets		2,151
Measurement Period Adjustments
Intangible assets		2,151
Matrix | Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets		2,198
Measurement Period Adjustments
Intangible assets		2,198
All Other 2023 Acquisitions
Business Acquisition [Line Items]
Cash		929		929
Accounts receivable and contract assets		3,422		3,441
Other current assets		353		439
Current assets		4,704		4,809
Property and equipment		1,705		1,705
Operating lease right-of-use asset—net		46		46
Other intangible assets		444		444
Goodwill		13,502		11,702
Total assets		28,314		27,300
Current liabilities		958		978
Operating lease liability—net of current portion		32		32
Deferred tax liability		1,103
Total liabilities		2,093		1,010
Purchase price		26,221		26,290
Measurement Period Adjustments
Accounts receivable and contract assets		(19)
Other current assets		(86)
Current assets		(105)
Goodwill		1,800
Total assets		1,014
Current liabilities		(20)
Deferred tax liability		1,103
Total liabilities		1,083
Purchase price		(69)
All Other 2023 Acquisitions | Customer Relationships
Business Acquisition [Line Items]
Intangible assets		7,181		7,741
Measurement Period Adjustments
Intangible assets		(560)
All Other 2023 Acquisitions | Trade Names
Business Acquisition [Line Items]
Intangible assets		222		222
All Other 2023 Acquisitions | Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets		510		631
Measurement Period Adjustments
Intangible assets		$ (121)
Environmental Standards
Business Acquisition [Line Items]
Cash				295
Accounts receivable and contract assets				5,200
Other current assets				456
Current assets				5,951
Property and equipment				168
Operating lease right-of-use asset—net				2,895
Goodwill				4,131
Total assets				20,231
Current liabilities				1,720
Operating lease liability—net of current portion				2,328
Total liabilities				4,048
Purchase price				16,183
Environmental Standards | Customer Relationships
Business Acquisition [Line Items]
Intangible assets				5,807
Environmental Standards | Trade Names
Business Acquisition [Line Items]
Intangible assets				1,010
Environmental Standards | Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets				269
All Other 2022 Acquisitions
Business Acquisition [Line Items]
Cash				824	824
Accounts receivable and contract assets				2,646	2,646
Other current assets				116	116
Current assets				3,586	3,586
Property and equipment				15	15
Operating lease right-of-use asset—net				215	215
Goodwill				8,253	8,412
Total assets				19,170	19,329
Current liabilities				1,314	1,314
Operating lease liability—net of current portion				110	110
Total liabilities				1,424	1,424
Purchase price				17,746	17,905
Measurement Period Adjustments
Goodwill				(159)
Total assets				(159)
Purchase price				(159)
All Other 2022 Acquisitions | Customer Relationships
Business Acquisition [Line Items]
Intangible assets				5,812	5,812
All Other 2022 Acquisitions | Trade Names
Business Acquisition [Line Items]
Intangible assets				639	639
All Other 2022 Acquisitions | Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets				$ 650	650
MSE Group
Business Acquisition [Line Items]
Cash					2,810
Accounts receivable and contract assets					2,980
Other current assets					31
Current assets					5,821
Property and equipment					513
Operating lease right-of-use asset—net					740
Goodwill					8,176
Total assets					25,413
Current liabilities					1,007
Operating lease liability—net of current portion					548
Total liabilities					1,555
Purchase price					23,858
MSE Group | Customer Relationships
Business Acquisition [Line Items]
Intangible assets					8,720
MSE Group | Trade Names
Business Acquisition [Line Items]
Intangible assets					521
MSE Group | Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets					922
EI
Business Acquisition [Line Items]
Cash					250
Accounts receivable and contract assets					4,675
Other current assets					84
Current assets					5,009
Property and equipment					32
Operating lease right-of-use asset—net					106
Goodwill					8,960
Total assets					25,687
Current liabilities					2,719
Operating lease liability—net of current portion					36
Total liabilities					2,755
Purchase price					22,932
EI | Customer Relationships
Business Acquisition [Line Items]
Intangible assets					10,073
EI | Trade Names
Business Acquisition [Line Items]
Intangible assets					996
EI | Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets					511
All Other 2021 Acquisitions
Business Acquisition [Line Items]
Cash					693
Accounts receivable and contract assets					4,133
Other current assets					289
Current assets					5,115
Property and equipment					1,168
Operating lease right-of-use asset—net					2,233
Goodwill					19,569
Total assets					44,442
Current liabilities					2,351
Operating lease liability—net of current portion					1,805
Total liabilities					4,156
Purchase price					40,286
All Other 2021 Acquisitions | Customer Relationships
Business Acquisition [Line Items]
Intangible assets					12,830
All Other 2021 Acquisitions | Trade Names
Business Acquisition [Line Items]
Intangible assets					1,958
All Other 2021 Acquisitions | Covenants Not to Compete
Business Acquisition [Line Items]
Intangible assets					1,248
All Other 2021 Acquisitions | Acquired Technology
Business Acquisition [Line Items]
Intangible assets					$ 321

[1] (1) The Company is continuing to obtain information to complete the valuation of certain of these acquisitions' assets and liabilities.