Stockholders'/Members' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended	6 Months Ended
	Jun. 14, 2021	Jun. 09, 2021	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2022	Dec. 31, 2021
Subsidiary Sale Of Stock [Line Items]
Common Stock, Shares Authorized					800,000,000	800,000,000
Common Stock, par value					$ 0.01	$ 0.01
Fair Value Of Mezzanine Equity				$ 36,750
Preferred Stock, Shares Authorized					25,000,000	25,000,000
Preferred Stock, par value					$ 0.01	$ 0.01
Preferred Stock, Shares Outstanding					0	0
Redeemable Class A Unit | Chief Executive Officer
Subsidiary Sale Of Stock [Line Items]
Shares, Issued					35,000,000
Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Conversion of Stock		10,234,000
IPO
Subsidiary Sale Of Stock [Line Items]
Shares Issued, Price Per Share					$ 18.00
Preferred Stock, Shares Authorized					25,000,000
Preferred Stock, par value					$ 0.01
Preferred Stock, Shares Outstanding					0	0
IPO | LifeStance [Member]
Subsidiary Sale Of Stock [Line Items]
Issuance of common , Shares	32,800,000
IPO | Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Issuance of common , Shares			32,800	32,800
IPO | Maximum
Subsidiary Sale Of Stock [Line Items]
Common Stock, Shares Authorized					800,000,000
IPO | Minimum
Subsidiary Sale Of Stock [Line Items]
Common Stock, Shares Authorized					1,000