Business Acquisitions - Total Purchase Price Allocation (Details) - USD ($) $ in Thousands					6 Months Ended
	Jan. 05, 2016	Apr. 30, 2015	Apr. 30, 2015	Apr. 21, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Business Acquisition [Line Items]
Cash		$ 3,789	$ 3,789
Accounts receivable		7,350	7,350
Inventory		5,008	5,008
Deferred tax assets and other current assets		457	457
Total current assets		16,604	16,604
Property and equipment		463	463
Intangible assets		14,051	14,051
Goodwill		26,197	26,197		$ 311,170		$ 147,906
Other non-current assets		52	52
Total assets		57,367	57,367
Current liabilities		7,809	7,809
Non-current deferred tax liabilities		3,833	3,833
Deferred service revenue and gross profit		3,242	3,242
Other non-current liabilities		1,056	1,056
Total purchase price		41,427	41,427
Total purchase price, net of cash received			37,638		$ 271,458	$ 23,625
Aesynt Holding, L.P., Aesynt, Ltd.
Business Acquisition [Line Items]
Cash	$ 8,200
Accounts receivable	44,412
Inventory	20,111
Other current assets	4,381
Total current assets	77,068
Property and equipment	10,389
Intangible assets	123,700
Goodwill	165,618
Other non-current assets	968
Total assets	377,743
Current liabilities	26,132
Deferred revenue, net	25,631
Non-current deferred tax liabilities	43,927
Other non-current liabilities	2,431
Total liabilities	98,121
Total purchase price	279,622
Total purchase price, net of cash received	$ 271,500
Mach4
Business Acquisition [Line Items]
Cash				$ 397
Accounts receivable				3,743
Inventory				3,580
Deferred tax assets and other current assets				368
Total current assets				8,088
Property and equipment				463
Intangible assets				7,710
Goodwill				10,591
Other non-current assets				52
Total assets				26,904
Current liabilities				3,684
Non-current deferred tax liabilities				2,564
Deferred service revenue and gross profit				2,314
Other non-current liabilities				1,056
Total purchase price				17,286
Total purchase price, net of cash received				$ 16,889
Avantec
Business Acquisition [Line Items]
Cash		3,392	3,392
Accounts receivable		3,607	3,607
Inventory		1,428	1,428
Deferred tax assets and other current assets		89	89
Total current assets		8,516	8,516
Property and equipment		0	0
Intangible assets		6,341	6,341
Goodwill		15,606	15,606
Other non-current assets		0	0
Total assets		30,463	30,463
Current liabilities		4,125	4,125
Non-current deferred tax liabilities		1,269	1,269
Deferred service revenue and gross profit		928	928
Other non-current liabilities		0	0
Total purchase price		24,141	$ 24,141
Total purchase price, net of cash received		$ 20,749