Segment and Related Information - Reconciliation of Segment Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Identifiable assets by geographic area [Abstract]
Identifiable assets	$ 127,215	$ 114,624
Goodwill by business segment [Abstract]
Goodwill	11,051	11,051
Restaurant/Retail
Goodwill by business segment [Abstract]
Goodwill	10,300	10,300
Government
Goodwill by business segment [Abstract]
Goodwill	800	800
Operating segments | Restaurant/Retail
Identifiable assets by geographic area [Abstract]
Identifiable assets	82,813	74,257
Goodwill by business segment [Abstract]
Goodwill	10,315	10,315
Operating segments | Government
Identifiable assets by geographic area [Abstract]
Identifiable assets	11,067	8,714
Goodwill by business segment [Abstract]
Goodwill	736	736
Reportable geographical components | United States
Identifiable assets by geographic area [Abstract]
Identifiable assets	113,612	99,284
Reportable geographical components | Other Countries
Identifiable assets by geographic area [Abstract]
Identifiable assets	13,603	15,340
Other
Identifiable assets by geographic area [Abstract]
Identifiable assets	$ 33,335	$ 31,653