CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
REVENUES	$ 328,243	$ 233,854	$ 188,805
COST OF REVENUES (exclusive of depreciation and amortization shown below)	215,492	163,983	134,734
SELLING, GENERAL AND ADMINISTRATIVE EXPENSE	78,638	49,109	40,953
INITIAL PUBLIC OFFERING EXPENSE	6,908	610
FAIR VALUE CHANGES IN BUSINESS ACQUISITIONS CONTINGENT CONSIDERATION	12,942	1,392	(158)
DEPRECIATION AND AMORTIZATION	37,274	27,705	23,915
INCOME (LOSS) FROM OPERATIONS	(23,011)	(8,945)	(10,639)
OTHER EXPENSE:
Other (expense) income	(20,268)	(10,978)	265
Interest expense—net	(13,819)	(6,755)	(11,085)
Total other expenses—net	(34,087)	(17,733)	(10,820)
LOSS BEFORE BENEFIT FROM INCOME TAXES	(57,098)	(26,678)	(21,459)
INCOME TAXES EXPENSE (BENEFIT)	851	(3,121)	(4,968)
NET INCOME (LOSS)	(57,949)	(23,557)	(16,491)
EQUITY ADJUSTMENT FROM FOREIGN CURRENCY TRANSLATION	111	(40)
COMPREHENSIVE LOSS	(57,838)	(23,597)	(16,491)
CONVERTIBLE PREFERRED STOCK DEEMED DIVIDEND, NET OF RETURN FROM HOLDERS			(932)
ACCRETION OF REDEEMABLE SERIES A- 1 PREFERRED STOCK	(17,601)	(19,616)	(3,605)
REDEEMABLE SERIES A-1 PREFERRED STOCK DEEMED DIVIDEND	(24,341)
CONVERTIBLE AND REDEEMABLE SERIES A-2 PREFERRED STOCK DIVIDEND	(6,970)
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ (106,861)	$ (43,173)	$ (21,028)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING—BASIC AND DILUTED	16,479	8,789	7,533
NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS—BASIC AND DILUTED	$ (6.48)	$ (4.91)	$ (2.79)