Acquisitions (Details) - USD ($) $ in Thousands					1 Months Ended	3 Months Ended		12 Months Ended
	Nov. 30, 2016	Feb. 02, 2016	Dec. 21, 2015	Nov. 04, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Sep. 30, 2016
Acquisitions
Net sales						$ 334,677	$ 313,813
Compensation expense						2,314	2,118
Net income (loss)						(2,868)	(5,414)
Change in fair value of contingent consideration						(1,314)	809
Amortization of purchased intangibles						9,355	6,455
Contingent consideration paid						1,988	1,679
Purchase price allocation
Goodwill					$ 408,372	408,372		$ 408,372	$ 406,946
Selling, general and administrative
Acquisitions
Compensation expense						2,139	1,799
Vocality
Acquisitions
Net sales					$ 100
Transaction and acquisition related costs						400
Net income (loss)						(900)
Fair value of consideration transferred	$ 9,600
Cash consideration paid	8,900
Contingent consideration	1,100
Purchase price allocation
Inventory	1,700
Accounts payable and accrued expenses	(400)
Other net liabilities assumed	(300)
Net identifiable assets acquired	5,900
Goodwill	3,700
Net assets acquired	$ 9,600
Weighted average useful life of intangible assets	9 years
Estimated amortization expense related to the intangible assets
2017									600
2018									800
2019									700
2020									600
2021									500
Thereafter									1,700
Vocality | Selling, general and administrative
Acquisitions
Compensation expense						400
Vocality | Customer relationships
Purchase price allocation
Amortizable intangible assets	$ 2,100
Vocality | Technology
Purchase price allocation
Amortizable intangible assets	2,400
Vocality | Trade names
Purchase price allocation
Amortizable intangible assets	$ 400
GATR
Acquisitions
Net sales						18,500
Net income (loss)						(300)
Change in fair value of contingent consideration						(400)
Amortization of purchased intangibles						3,600
Fair value of consideration transferred		$ 220,500
Cash consideration paid		236,100
Contingent consideration		2,500
Cash paid related to compensation expenses		$ 18,100
Period for contingent consideration contracts		12 months
Purchase price allocation
Accounts receivable		$ 10,600
Inventory		3,400
Income tax receivable		5,100
Accounts payable and accrued expenses		(2,400)
Tax liabilities		(23,800)
Net identifiable assets acquired		64,600
Goodwill		155,900
Net assets acquired		$ 220,500
Weighted average useful life of intangible assets		9 years
Estimated amortization expense related to the intangible assets
2017									12,700
2018									11,100
2019									9,800
2020									8,300
2021									6,900
Thereafter									13,200
GATR | Maximum
Acquisitions
Contingent consideration		$ 7,500
GATR | Customer relationships
Purchase price allocation
Amortizable intangible assets		51,700
GATR | Backlog
Purchase price allocation
Amortizable intangible assets		3,400
GATR | Technology
Purchase price allocation
Amortizable intangible assets		10,700
GATR | Non-compete agreements
Purchase price allocation
Amortizable intangible assets		1,200
GATR | Trade names
Purchase price allocation
Amortizable intangible assets		$ 4,700
TeraLogics
Acquisitions
Net sales						6,200
Compensation expense							1,300
Transaction and acquisition related costs							400
Net income (loss)						(100)	(1,500)
Change in fair value of contingent consideration						2,900
Amortization of purchased intangibles						1,000
Fair value of consideration transferred			$ 33,900
Cash consideration paid			28,900
Contingent consideration			5,000
Contingent consideration paid								$ 32,400
Purchase price allocation
Accounts receivable			1,400
Accounts payable and accrued expenses			(500)
Other net liabilities assumed			(100)
Net identifiable assets acquired			15,700
Goodwill			18,200
Net assets acquired			$ 33,900
Weighted average useful life of intangible assets			7 years
Estimated amortization expense related to the intangible assets
2017									3,500
2018									2,800
2019									2,100
2020									1,400
2021									800
Thereafter									$ 1,400
TeraLogics | Maximum
Acquisitions
Contingent consideration			$ 9,000
TeraLogics | Maximum | Revenue thresholds
Acquisitions
Contingent consideration			6,000
TeraLogics | Maximum | Contract extensions
Acquisitions
Contingent consideration			3,000
TeraLogics | Customer relationships
Purchase price allocation
Amortizable intangible assets			6,700
TeraLogics | Backlog
Purchase price allocation
Amortizable intangible assets			5,600
TeraLogics | Software
Purchase price allocation
Amortizable intangible assets			2,500
TeraLogics | Non-compete agreements
Purchase price allocation
Amortizable intangible assets			$ 100
H4 Global
Acquisitions
Net sales						700
Transaction and acquisition related costs							$ 100
Net income (loss)						$ 200
Fair value of consideration transferred				$ 1,900
Cash consideration paid				900
Contingent consideration				$ 1,000
Period for contingent consideration contracts				5 years
Purchase price allocation
Goodwill				$ 1,900
H4 Global | Maximum
Acquisitions
Contingent consideration				$ 4,100