Business Combinations - Narrative (Details) $ in Thousands		12 Months Ended
	Oct. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) company	Dec. 31, 2017 USD ($) company
Business Acquisition [Line Items]
Goodwill		$ 156,756	$ 148,845	$ 128,728
Developed technology
Business Acquisition [Line Items]
Weighted average useful life (in years)		5 years
2019 Business Combination
Business Acquisition [Line Items]
Payments to acquire businesses		$ 7,500
Net deferred tax liabilities		1,400
Goodwill		2,200
2019 Business Combination | Developed technology
Business Acquisition [Line Items]
Developed technology		$ 3,000
Weighted average useful life (in years)		5 years
2019 Business Combination | Backlog Intangible Assets
Business Acquisition [Line Items]
Developed technology		$ 2,500
Weighted average useful life (in years)		2 years
2018 Business Combinations
Business Acquisition [Line Items]
Payments to acquire businesses			37,600
Net deferred tax liabilities			2,200
Goodwill			$ 26,100
Number of business combinations | company			4
Goodwill, tax deductible amount			$ 8,000
2018 Business Combinations | Developed technology
Business Acquisition [Line Items]
Developed technology			$ 13,500
Weighted average useful life (in years)			5 years
SkyGiraffe Inc.
Business Acquisition [Line Items]
Payments to acquire businesses	$ 32,300
Net deferred tax liabilities	3,300
Goodwill	19,400
SkyGiraffe Inc. | Developed technology
Business Acquisition [Line Items]
Developed technology	$ 15,600
Estimated useful life of intangible assets (in years)	5 years
Other 2017 Business Combinations
Business Acquisition [Line Items]
Payments to acquire businesses				26,600
Developed technology				9,900
Net deferred tax liabilities				3,600
Goodwill				$ 20,300
Number of business combinations | company				3
Goodwill, tax deductible amount				$ 4,100
Other 2017 Business Combinations | Developed technology
Business Acquisition [Line Items]
Weighted average useful life (in years)				5 years