Off-Balance Sheet Financial Instruments, Commitments and Contingencies and Concentrations of Risks - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Loan commitments	$ 58,835,208	$ 46,405,869
Letters of credit outstanding	$ 2,516,810	$ 2,842,010

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant