CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
OPERATING ACTIVITIES:
Net loss	$ (57,949)	$ (23,557)	$ (16,491)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Provision for bad debt	4,532	1,246
DEPRECIATION AND AMORTIZATION	37,274	27,705	23,915
Stock-based compensation expense	4,849	4,345	5,794
Fair value changes in embedded derivatives	11,007	7,100	(352)
Fair value changes in business acquisitions contingent consideration	12,942	1,392	(158)
Fair value changes in the warrant options	9,312	4,060
Deferred income taxes	851	(3,121)	(4,968)
Amortization of deferred financing costs	1,810	560	1,672
Other	278	(363)	(406)
Changes in operating assets and liabilities—net of acquisitions:
Accounts receivable and contract assets	(19,202)	(6,588)	(9,997)
Prepaid expenses and other current assets	(956)	(2,461)	(101)
Accounts payable and other accrued liabilities	601	6,085	(2,202)
Accrued payroll and benefits	6,072	2,248	449
Payment of contingent consideration and other assumed purchase price obligations	(6,390)
Other assets	(3,181)	(1,609)
Net cash provided by (used in) operating activities	1,850	17,042	(2,845)
INVESTING ACTIVITIES:
Proceeds from property insurance		360	43
Purchases of property and equipment	(7,206)	(4,692)	(3,772)
Proceeds received from the sale of property and equipment	20	260	166
Proprietary software development and software licenses costs	(570)	(21)	(337)
Payment of assumed purchase price obligations		(1,520)	(548)
Proceeds from net working capital adjustment related to acquisitions	1,939
Cash paid for acquisitions—net of cash acquired	(173,923)	(81,370)	(45,835)
Net cash used in investing activities	(179,740)	(86,983)	(50,283)
FINANCING ACTIVITIES:
Proceeds from line of credit	104,390	146,338	109,383
Payments on line of credit	(201,980)	(68,747)	(89,383)
Proceeds from term loans	175,000		35,333
Repayment of term loans	(49,844)	(1,250)	(71,590)
Payment of contingent consideration and other assumed purchase price obligations	(6,004)	(1,113)	(2,009)
Repayment of capital leases	(2,848)	(1,972)	(1,010)
Proceeds from issuance of common stock in connection with initial public offering, net of issuance costs	161,288
Payments of deferred offering costs	(4,164)
Debt issuance and extinguishment cost	(5,217)	(435)	(1,299)
Proceeds from issuance of common stock	408	1,509	30
Issuance of series A-1 and series A-2 preferred stock and warrant, net of issuance costs	173,664		118,419
Redemption of the series A-1 preferred stock	(131,821)
Dividend payment to the series A-2 shareholders	(6,970)
Collection of notes receivable		122
Repayment of subordinated debt			(11,944)
Repurchase of options			(1,372)
Conversion of convertible preferred stock into cash			(30,986)
Repurchase of common stock			(2,722)
Net cash provided by financing activities	205,902	74,452	50,850
CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	28,012	4,511	(2,278)
Foreign exchange impact on cash balance	(15)	(116)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Beginning of year	6,884	2,489	4,767
End of year	34,881	6,884	2,489
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION:
Cash paid for interest	11,947	5,891	7,924
Cash paid for income tax	171	1,205	596
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Preferred stock deemed dividend—net of return from holders	24,341		932
Redemption of preferred stock in common shares	26,801		14,963
Accrued purchases of property and equipment	432	975	793
Property and equipment purchased under capital leases	2,113	4,347	3,116
Accretion of the redeemable series A-1 preferred stock to redeemable value	17,601	19,616	3,605
Common stock issued to acquire new businesses	25,000	4,047	5,634
Acquisitions unpaid contingent consideration	$ 54,467	5,402	4,760
Offering costs included in accounts payable and other accrued liabilities		$ 1,240	154
Write off of the subordinated debt embedded derivative			$ 2,295