General form of registration statement for all companies including face-amount certificate companies

Goodwill and Intangible Assets - Weighted-average remaining useful life (Details)

v3.21.2
Goodwill and Intangible Assets - Weighted-average remaining useful life (Details) - USD ($)
 9 Months Ended 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]          
Impairment of intangible assets $ 0 $ 0 $ 0 $ 0 $ 0
Trademarks and brands          
Finite-Lived Intangible Assets [Line Items]          
Remaining useful life 11 years   11 years    
Customer relationships          
Finite-Lived Intangible Assets [Line Items]          
Remaining useful life 8 years   9 years    
Developed Technology          
Finite-Lived Intangible Assets [Line Items]          
Remaining useful life 4 years   5 years    
Non-compete agreements          
Finite-Lived Intangible Assets [Line Items]          
Remaining useful life 2 years