Divestiture and Discontinued Operations (Details) - USD ($) $ in Thousands			3 Months Ended
	May 05, 2017	Nov. 04, 2015	Mar. 31, 2018	Mar. 31, 2017
Operations
Income from discontinued operations, net of taxes			$ 0	$ 183
PAR Springer-Miller Systems, Inc.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total consideration		$ 16,600
Consideration received	$ 4,200	12,100
Consideration payable period from closing date			18 months
Consideration could be received upon achievement of targets		1,500
Consideration could be received upon achievement of targets per year		500
Operations
Total revenues			$ 0	0
Income from discontinued operations before income taxes			0	284
Provision for income taxes			0	(101)
Income from discontinued operations, net of taxes			$ 0	$ 183
PAR Springer-Miller Systems, Inc. | Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration receivable		$ 4,500