Long-Term Borrowings - Summary of Weighted Average Interest Rate on Subordinated Notes (Detail)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Subordinated notes weighted average interest rate	3.23%	3.33%	3.08%

Weighted average interest rate of long-term debt outstanding calculated at point in time.

No definition available.

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant