Business Description - Additional Information (Details) $ / shares in Units, $ in Millions		9 Months Ended
	Mar. 27, 2018 USD ($) $ / shares shares	Sep. 30, 2018 Branch Office shares
Business Description [Line Items]
Operations commenced date		Jun. 01, 2016
Number of full service branches | Branch		8
Number of loan production offices | Office		3
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	$ 22.6
Initial Public Offering
Business Description [Line Items]
Underwriting Discounts and Commissions	1.7
Payments of Stock Issuance Costs	$ 925,000.0
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
Open Bank
Business Description [Line Items]
Percentage of voting equity interests acquired		100.00%
Operations commenced date		Jun. 10, 2005