Acquisitions - Semma Therapeutics (Details) - USD ($)	Oct. 10, 2019	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Property and equipment, net			$ 758,085,000	$ 812,005,000
Goodwill		$ 1,002,158,000		50,384,000
Intangible asset		400,000,000.0		$ 0
Semma Therapeutics, Inc.
Business Acquisition [Line Items]
Cash and cash equivalents	$ 29,331,000
Property and equipment, net	17,111,000
Deferred tax liability		(54,200,000)
Net other assets	2,849,000
Total purchase price	936,764,000
Semma Therapeutics, Inc.
Business Acquisition [Line Items]
Goodwill	554,633,000	554,600,000
Intangible asset	387,000,000	$ 387,000,000.0
Deferred tax liability	$ (54,160,000)