Leases (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($) Option	Sep. 30, 2021 USD ($) Option
Operating Lease [Abstract]
Number of options to extend | Option	1	1
Operating lease, extension term	5 years	5 years
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Office properties and equipment, net	Office properties and equipment, net
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Accrued expenses and other liabilities	Accrued expenses and other liabilities
Rent expense under operating lease | $	$ 0	$ 0