Acquisitions - Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 21, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets acquired:
Goodwill	$ 873,779		$ 806,421	$ 806,421
Aurelia Health, LLC
Assets acquired:
Cash		$ 330
Accounts receivable		7,189
Current assets		9,974
Property and equipment, net		699
Other assets		3,182
Identified intangible assets		38,011
Goodwill		67,358
Total assets acquired		119,224
Liabilities assumed:
Current liabilities		1,825
Other liabilities		4,294
Total liabilities assumed		6,119
Net assets acquired		113,105
Redeemable non-controlling interest		33,006
Total Consideration		$ 80,099