Acquisitions - Narrative (Details)					3 Months Ended				9 Months Ended
	Feb. 14, 2020 USD ($)	Dec. 19, 2019 USD ($)	Jun. 14, 2019 USD ($)	Jan. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) acquisition	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Feb. 09, 2018 USD ($)
Business Acquisition [Line Items]
Number of acquisitions | acquisition									4
Cash consideration									$ 476,491,000	$ 228,222,000
Goodwill					$ 869,941,000				869,941,000		$ 595,551,000
Revenue					551,631,000			$ 567,597,000	1,762,443,000	1,635,215,000
Income before income taxes					33,898,000			31,909,000	85,545,000	110,379,000
Interest expense					12,564,000			7,830,000	35,061,000	19,568,000
Stratus and Advanced
Business Acquisition [Line Items]
Acquisition-related costs					1,023,000				11,662,000
Incremental acquisition-related costs								4,512,000		20,438,000
Amortization of intangible assets								1,307,000		10,924,000
Interest expense								1,246,000		5,465,000
Stratus Video
Business Acquisition [Line Items]
Cash consideration	$ 485,568,000					$ 99,000
Acquisition-related costs									10,548,000
Initial purchase price						485,667,000
Fair value of tangible assets acquired						44,880,000
Cash and restricted cash received						9,176,000
Liabilities assumed						61,640,000
Identifiable intangible assets	$ 228,000,000					228,000,000
Goodwill						274,427,000
Goodwill expected to be deductible for tax purposes						$ 10,186,000
Intangible assets acquired, weighted average useful life	17 years
Revenue					35,329,000				78,080,000
Income before income taxes					$ 8,322,000				$ 13,787,000
Stratus Video | Tradenames and Trademarks
Business Acquisition [Line Items]
Identifiable intangible assets	$ 40,000,000
Useful life					5 years
Stratus Video | Tradenames and Trademarks | Maximum
Business Acquisition [Line Items]
Useful life	10 years
Stratus Video | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets	$ 16,000,000
Useful life	5 years
Stratus Video | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets	$ 171,000,000
Useful life	20 years
Advanced
Business Acquisition [Line Items]
Cash consideration			$ 201,121,000					73,000
Initial purchase price			211,743,000
Fair value of tangible assets acquired								29,020,000		29,020,000
Cash and restricted cash received								2,497,000		2,497,000
Liabilities assumed								28,772,000		28,772,000
Identifiable intangible assets			$ 91,700,000					91,700,000		91,700,000
Goodwill								119,868,000		119,868,000
Goodwill expected to be deductible for tax purposes								57,236,000		$ 57,236,000
Intangible assets acquired, weighted average useful life			9 years
Contingent earn-out payment (up to)			$ 20,000,000
Estimated fair value of contingent earn-out payment			10,622,000
Purchase price, net of working capital adjustments								$ 211,816,000
Advanced | Tradenames and Trademarks
Business Acquisition [Line Items]
Identifiable intangible assets			$ 10,000,000
Useful life			5 years
Advanced | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets			$ 3,400,000
Useful life			3 years
Advanced | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets			$ 68,000,000
Useful life			10 years
b4health
Business Acquisition [Line Items]
Cash consideration		$ 19,906,000
Initial purchase price		$ 23,006,000
Fair value of tangible assets acquired							$ 1,169,000
Cash and restricted cash received							222,000
Liabilities assumed							823,000
Identifiable intangible assets							9,000,000
Goodwill							13,594,000
Intangible assets acquired, weighted average useful life		7 years
Contingent earn-out payment (up to)		$ 12,000,000
Estimated fair value of contingent earn-out payment		$ 3,100,000
Final working capital settlement							66,000
Purchase price, net of working capital adjustments							22,940,000
b4health | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets							3,000,000
b4health | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets							4,000,000
b4health | Trademarks
Business Acquisition [Line Items]
Identifiable intangible assets							$ 2,000,000
Silversheet
Business Acquisition [Line Items]
Cash consideration				$ 30,176,000
Initial purchase price				31,676,000
Fair value of tangible assets acquired				2,826,000
Cash and restricted cash received				651,000
Liabilities assumed				1,567,000
Identifiable intangible assets				6,880,000
Goodwill				$ 23,537,000
Intangible assets acquired, weighted average useful life				8 years
Contingent earn-out payment (up to)				$ 25,000,000
Estimated fair value of contingent earn-out payment				1,500,000
Silversheet | Based on operating results for the twelve months ending December 31, 2019
Business Acquisition [Line Items]
Contingent earn-out payment (up to)				6,000,000
Silversheet | Based on operating results for the twelve months ending December 31, 2020
Business Acquisition [Line Items]
Contingent earn-out payment (up to)				19,000,000
Silversheet | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets				5,300,000
Silversheet | Trademarks
Business Acquisition [Line Items]
Identifiable intangible assets				$ 1,500,000
Revolving Credit Facility | Line of Credit
Business Acquisition [Line Items]
Maximum borrowing capacity												$ 400,000,000
Term Loan | Term Debt
Business Acquisition [Line Items]
Term loan credit facility	$ 250,000,000		$ 150,000,000