Loans - Purchased Credit Impaired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Loans | Commercial and industrial
Loans Held for Investment
Total purchase credit impaired	$ 7,755	$ 1,071	$ 1,585
Business Loans | Commercial owner occupied
Loans Held for Investment
Total purchase credit impaired	0	628	98
Business Loans | SBA
Loans Held for Investment
Total purchase credit impaired	4,070	7,598	4,329
Real Estate Loans | Commercial non-owner occupied
Loans Held for Investment
Total purchase credit impaired	1,184	0	0
Real Estate Loans | One-to-four family
Loans Held for Investment
Total purchase credit impaired	412	453	849
Real Estate Loans | Construction
Loans Held for Investment
Total purchase credit impaired			0
Real Estate Loans | Land
Loans Held for Investment
Total purchase credit impaired	0	0	$ 35
Consumer Loans | Consumer loans
Loans Held for Investment
Total purchase credit impaired	$ 0	$ 0