UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
OPERATING ACTIVITIES:
Net loss	$ (14,483)	$ 13,224		$ (26,079)	$ (28,024)
Adjustments to reconcile net loss to net cash used in operating activities:
Provision for bad debt			$ 6,300	590	6,263	$ 4,532
DEPRECIATION AND AMORTIZATION	10,905	9,784		21,674	17,344
Amortization of right-of-use asset				4,025
Stock-based compensation expense	2,417	1,140		4,222	2,290
Fair value changes in embedded derivatives				1,120	7,781
FAIR VALUE CHANGES IN BUSINESS ACQUISITIONS CONTINGENT CONSIDERATION	12,971	3,983		24,035	3,983
Deferred income taxes				(254)	(4,911)
Other				(87)	983
Debt extinguishment costs				4,052
Changes in operating assets and liabilities—net of acquisitions:
Accounts receivable and contract assets				(31,009)	7,427
Prepaid expenses and other current assets				1,316	(789)
Accounts payable and other accrued liabilities				1,788	(8,296)
Accrued payroll and benefits				(2,846)	1,886
Payment of contingent consideration and other assumed purchase price obligations				(15,549)	(6,175)
Other assets				(107)	(1,346)
Change in operating leases				(3,937)
Net cash used in operating activities				(17,046)	(1,584)
INVESTING ACTIVITIES:
Purchases of property and equipment				(2,354)	(3,160)
Proprietary software development and other software costs				(208)	(155)
Purchase price true ups				(8,377)
Proceeds from net working capital adjustment related to acquisitions					2,819
Cash paid for acquisitions—net of cash acquired				(14,876)	(173,473)
Net cash used in investing activities				(25,815)	(173,969)
FINANCING ACTIVITIES:
Proceeds from line of credit				105,000	104,390
Payments on line of credit				(40,000)	(176,980)
Proceeds from term loans				175,000	175,000
Repayment of term loan				(173,905)	(48,750)
Payment of contingent consideration and other purchase price obligations				(9,605)	(6,005)
Repayment of finance leases				(1,143)	(1,249)
Payments of deferred offering costs					(1,462)
Prepayment premium on credit facility					(351)
Debt issuance costs				(2,590)	(4,866)
Proceeds from issuance of common stock for exercised stock options				3,086	21
Issuance of convertible and redeemable Series A-2 preferred stock and warrant					173,664
Dividend payment to the Series A-2 shareholders				(8,200)
Net cash provided by financing activities				47,643	213,412
CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH				4,782	37,859
Foreign exchange impact on cash balance				526	71
Beginning of year			$ 6,884	34,881	6,884	6,884
End of period	$ 40,189	$ 44,814		40,189	44,814	$ 34,881
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION:
Cash paid for interest				3,397	6,539
Cash paid for income tax				305	72
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Accrued purchases of property and equipment				907	814
Property and equipment purchased under finance leases				1,766	1,704
Accretion of the redeemable series A-1 preferred stock to redeemable value					11,059
Common stock issued to acquire new businesses				2,746	25,000
Acquisitions unpaid contingent consideration				31,152	44,994
Offering costs included in accounts payable and other accrued liabilities					$ 941
Acquisitions contingent consideration paid in shares				$ 25,000