Business Combinations - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended		9 Months Ended
	Oct. 31, 2016	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 1,151,216	$ 1,151,216	$ 1,150,244
Concord Systems, Inc. [Member]
Business Acquisition [Line Items]
Cash consideration		3,000
Goodwill		1,100	1,100
Intangible assets acquired		$ 2,800
Weighted average useful life		7 years
Deferred tax liability		$ 900	900
Goodwill expected to be tax deductible		$ 300	300
Soha Systems, Inc. [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Total purchase consideration	$ 55,000
Consideration for achievement of post-closing milestones	$ 5,000
General and Administrative Expense [Member]
Business Acquisition [Line Items]
Acquisition-related costs			$ 1,000