Segment Information - Reconciliation of Segment Measure to Loss Before Benefit from Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Total									$ 54,476	$ 31,495	$ 21,817
Interest expense, net	$ (2,923)	$ (3,043)	$ (5,260)	$ (2,593)	$ (2,165)	$ (2,130)	$ (1,181)	$ (1,279)	(13,819)	(6,755)	(11,085)
Income tax (expense) benefit	(2,414)	(3,348)	1,759	3,152	1,813	412	1,712	(816)	(851)	3,121	4,968
Depreciation and amortization	$ (10,190)	$ (9,740)	$ (9,784)	$ (7,560)	$ (7,443)	$ (7,412)	$ (6,401)	$ (6,449)	(37,274)	(27,705)	(23,915)
Stock-based compensation									(4,849)	(4,345)	(5,794)
Start-up losses and investment in new services									(2,182)	(1,874)	(999)
Acquisition costs									(4,344)	(3,474)	(1,595)
Fair value changes in embedded derivatives									(11,007)	(11,160)	352
Fair value changes in warrant options									(9,312)
Fair value changes in business acquisitions contingent consideration									(12,942)	(1,392)	158
Short term purchase accounting fair value adjustment to deferred revenue									(243)	(858)
Initial public offering expense and secondary offering costs									(7,657)	(610)
Discontinued services									(5,662)
Expenses related to financing transactions									(378)		(398)
Other expenses									(1,905)
Net loss									$ (57,949)	$ (23,557)	$ (16,491)