Business Combinations - Preliminary Allocation of the Purchase Price to the Assets Acquired and the Liabilities Assumed By the Company (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Oct. 01, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill	$ 499,309		$ 336,539	$ 335,887
340B Link Business
Business Acquisition [Line Items]
Accounts receivable and unbilled receivables		$ 8,197
Prepaid expenses		232
Other current assets		22,747
Total current assets		31,176
Property and equipment		531
Operating lease right-of-use assets		3,138
Goodwill		161,117
Intangible assets		62,800
Total assets		258,762
Accounts payable		568
Accrued liabilities		23,787
Long-term deferred tax liabilities		6,818
Long-term operating lease liabilities		2,589
Total liabilities		33,762
Total purchase price		$ 225,000