Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, $ in Thousands				3 Months Ended			9 Months Ended		12 Months Ended
	Nov. 09, 2021 USD ($) shares	Jun. 11, 2021	Jun. 03, 2021 USD ($) $ / shares shares	Sep. 30, 2021 USD ($) plan shares	Jun. 30, 2021 USD ($) shares	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) plan shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Impact of transactions affecting non-controlling interests				$ 0			$ 0
Class of Warrant or Right [Line Items]
Number of days from which warrants become exercisable after the consummation of business combination			30 days
Warrants and rights outstanding term			5 years
Share price | $ / shares			$ 18.00
Concentration Risk [Line Items]
Concentration risk percentage				100.00%		100.00%	100.00%	100.00%
Cash FDIC Insured Amount				$ 300			$ 300
Number of health plan | plan				2			2
Restricted cash balances				$ 3,500			$ 3,500
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts receivable				0			0		$ 0
Accounts receivable				223,644			223,644		76,709
Unpaid service cost incurred in previous year							3,526	$ 793
Malpractice Insurance [Line Items]
Loss contingency insurance policy, deductible							100		100
Loss contingency insurance policy, Maximum Coverage limit									2,000
Loss contingency insurance policy, Premiums				1,900		$ 1,300	5,400	3,600
Loss contingency insurance policy, insurance reimbursements				3,600		0	5,400	0
Insurance recoveries							3,500		2,500
Extinguishment of Debt [Line Items]
Debt issuance costs and debt discounts premium, net				24,200			24,200		24,900
Extinguishment of debt			$ 400,000
Loss on extinguishment of debt				0		0	13,225	0
Amortization of debt issuance costs				4,000		3,000	7,700	3,900
Extinguishment of debt			$ 400,000
Loss on extinguishment of debt				$ 0		0	13,225	0
Property, Plant and Equipment [Line Items]
Impairment to goodwill							$ 0	0
Class A common stock
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Stock issued during period, acquisitions (in shares) | shares				4,178,147	4,178,147
Income Tax Disclosure [Line Items]
Issuance of common stock for acquisitions (in shares) | shares				4,178,147	4,178,147
Issuance of common stock for acquisitions (in shares) | shares				4,178,147	4,178,147
Subsequent Event | Primary Care Intermediate Holdings, LLC
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Number of shares of equity interests issued to acquire entity (in shares) | shares	4,178,147
Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets							1 year
Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets							20 years
University Health Care And Its Affiliates
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets		5 years
Medicare risk adjustment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable				$ 108,600			$ 108,600		18,100
Primary Care ITC Intermediate Holdings LLC
Income Tax Disclosure [Line Items]
Percentage of non controlling ownership			64.90%
Percentage of controlling ownership			35.10%
Primary Care ITC Intermediate Holdings LLC | University Health Care And Its Affiliates
Income Tax Disclosure [Line Items]
Percentage of non controlling ownership				64.00%			64.00%
Percentage of controlling ownership				36.00%			36.00%
Former Stock Holders Of Jaws And Pipe Investors
Income Tax Disclosure [Line Items]
Percentage of managing rights				100.00%			100.00%
Leaseholds and Leasehold Improvements | Minimum
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life							3 years
Leaseholds and Leasehold Improvements | Maximum
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life							15 years
Professional and General Liability
Malpractice Insurance [Line Items]
Malpractice insurance policy with a coverage limit							$ 1,000
Malpractice insurance policy with a aggregate coverage limit							3,000
Umbrella Insurance policy coverage							5,000
Insurance claim liabilities				$ (500)			(500)		$ (100)
Selling, General and Administrative Expenses
Schedule of Marketing and Advertising Expense [Line Items]
Advertising and marketing expense				4,900		$ 2,400	10,500	$ 4,900
Non-Controlling Interests
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Impact of transactions affecting non-controlling interests				(39,550)	$ (38,600)		(39,550)
Non-Controlling Interests | Subsequent Event
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Impact of transactions affecting non-controlling interests	$ (39,600)
Additional Paid-in Capital
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Impact of transactions affecting non-controlling interests				$ 39,550	$ 38,600		$ 39,550
Additional Paid-in Capital | Subsequent Event
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Impact of transactions affecting non-controlling interests	$ 39,600
Supplier Benchmark | Significant Vendor | Supplier Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage				87.00%		100.00%	96.00%	100.00%
Revenue Benchmark | Customer Concentration Risk | Three HMOs
Concentration Risk [Line Items]
Concentration risk percentage				57.20%		70.20%	63.60%	67.50%
Accounts receivable | Customer Concentration Risk | Three HMOs
Concentration Risk [Line Items]
Concentration risk percentage							39.80%		67.10%
Public Warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares) | shares			23,000,000.0	23,000,000.0			23,000,000.0
Private Placement Warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares) | shares			10,530,000	10,530,000			10,530,000
Notes Payable
Extinguishment of Debt [Line Items]
Debt issuance costs and debt discounts premium, net				$ 23,500			$ 23,500		$ 18,500
Prepaid Expenses and Other Current Assets
Extinguishment of Debt [Line Items]
Debt issuance costs and debt discounts premium, net				200			200		5,800
Other Assets
Extinguishment of Debt [Line Items]
Debt issuance costs and debt discounts premium, net				$ 500			$ 500		$ 600