Business Description - Additional Information (Details)		3 Months Ended
	Mar. 27, 2018 USD ($) $ / shares shares	Mar. 31, 2019 Branch Office	Mar. 31, 2018 shares
Business Description [Line Items]
Operations commenced date		Jun. 01, 2016
Number of full service branches | Branch		9
Number of loan production offices | Office		5
Common Stock
Business Description [Line Items]
Stock issued under stock offering, net of expenses, shares | shares			2,300,000
Proceeds from issuance initial public offering	$ 22,600,000
Initial Public Offering | Common Stock
Business Description [Line Items]
Stock issued under stock offering, net of expenses, shares | shares	2,300,000
Stock price per shre | $ / shares	$ 11.00
Payments for underwriting discounts and commissions	$ 1,700,000
Payments of stock offering expenses	$ 925,000
Open Bank
Business Description [Line Items]
Percentage of voting equity interests acquired		100.00%
Operations commenced date		Jun. 10, 2005