Segment Information - Schedule of Segment Information for Entity's Continuing Operations (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net sales		$ 533,989	$ 542,832
Gross profit (loss)		83,114	83,596
Operating profit (loss)		8,427	6,242
Commercial [Member]
Segment Reporting Information [Line Items]
Net sales		428,528	414,731
Gross profit (loss)		66,430	65,848
Depreciation and amortization expense	[1]	1,251	1,363
Operating profit (loss)		22,645	21,717
Public Sector [Member]
Segment Reporting Information [Line Items]
Net sales		40,047	56,062
Gross profit (loss)		5,076	6,024
Depreciation and amortization expense	[1]	102	175
Operating profit (loss)		141	50
Canada [Member]
Segment Reporting Information [Line Items]
Net sales		47,193	54,120
Gross profit (loss)		7,984	8,361
Depreciation and amortization expense	[1]	190	266
Operating profit (loss)		1,553	1,462
United Kingdom [Member]
Segment Reporting Information [Line Items]
Net sales		18,374	18,073
Gross profit (loss)		3,778	3,515
Depreciation and amortization expense	[1]	78	49
Operating profit (loss)		(544)	(292)
Corporate & Other [Member]
Segment Reporting Information [Line Items]
Net sales		(153)	(154)
Gross profit (loss)		(154)	(152)
Depreciation and amortization expense	[1]	1,514	1,752
Operating profit (loss)		(15,368)	(16,695)
Consolidated [Member]
Segment Reporting Information [Line Items]
Net sales		533,989	542,832
Gross profit (loss)		83,114	83,596
Depreciation and amortization expense	[1]	3,135	3,605
Operating profit (loss)		$ 8,427	$ 6,242

[1] Primary fixed assets relating to network and servers are managed by the Corporate headquarters. As such, depreciation expense relating to such assets is included as part of Corporate & Other.