Segment and Related Information - Summary of Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) reporting_unit	Mar. 31, 2020 USD ($)
Segment and Related Information [Abstract]
Number of operating segments | reporting_unit	2
Number of reportable segments | reporting_unit	2
Information as to the Company's segments [Abstract]
Revenue	$ 54,467	$ 54,732
Operating loss	(6,021)	(5,674)
Other expense – net	(51)	(406)
Interest expense, net	(2,160)	(1,972)
Loss on extinguishment of debt	0	(8,123)
Net loss	(8,232)	(16,175)
Depreciation, amortization and accretion	3,990	3,142
Capital expenditures including software costs	1,669	2,040
United States
Information as to the Company's segments [Abstract]
Revenue	50,603	52,631
Other Countries
Information as to the Company's segments [Abstract]
Revenue	3,864	2,101
Restaurant and Retail
Information as to the Company's segments [Abstract]
Revenue	36,584	37,409
Government Segment
Information as to the Company's segments [Abstract]
Revenue	17,883	17,323
Operating segments | Restaurant and Retail
Information as to the Company's segments [Abstract]
Operating loss	(9,285)	(6,070)
Depreciation, amortization and accretion	2,429	1,855
Capital expenditures including software costs	1,517	1,707
Operating segments | Government Segment
Information as to the Company's segments [Abstract]
Operating loss	1,190	1,179
Depreciation, amortization and accretion	36	16
Capital expenditures including software costs	152	211
Corporate, Non-Segment
Information as to the Company's segments [Abstract]
Operating loss	2,074	(783)
Depreciation, amortization and accretion	1,525	1,271
Capital expenditures including software costs	$ 0	$ 122