Investments - Other Investments - Additional Information (Detail)	Dec. 31, 2021 USD ($) Venture Investment	Dec. 31, 2020 USD ($)
Schedule of Equity Method Investments [Line Items]
Assets	$ 5,500,000	$ 22,400,000
Non controlling interest certified low-income housing developments | Investment	7
Liabilities	$ 24,784,900,000	16,098,700,000
Other Investments [Member]
Schedule of Equity Method Investments [Line Items]
Assets	5,500,000	$ 3,900,000
Other Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Equity Method Investments [Line Items]
Assets	4,800,000
Liabilities	$ 500,000
Other Investments [Member] | One Startup Venture [Member]
Schedule of Equity Method Investments [Line Items]
Non-controlling interest in startup venture number | Venture	1
Assets	$ 1,600,000
Other Investments [Member] | Four Venture Capital Funds [Member]
Schedule of Equity Method Investments [Line Items]
Assets	$ 3,900,000
Non controlling interest in venture capital funds number | Venture	4
Other Investments [Member] | Seven Certified Low Income Housing Developments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value of investments	$ 0