Loans and Allowance for Loan Losses Loans and Allowance for Loan Losses - Narrative (Details)	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructuring, Modifications, Number of Contracts	0	0
Percentage of loan portfolio as commercial loan	81.10%
Risk rated loans	$ 1,000,000
Average balance of impaired loans	89,575,000	$ 64,223,000
Cash payments received on nonaccrual loans	87,000
Nonaccrual loans	1,600,000	1,400,000
Troubled debt restructurings performing as of restructure date	$ 5,480,000		$ 5,890,000
Percentage of credit exposure to risk based capital	25.00%
Loans and other extensions of credit granted to directors, executive officers, and their related entities	$ 38,400,000		37,900,000
Amount drawn from loans and other extensions of credit granted	18,100,000		18,300,000
Commercial loans held-for-sale	14,456,000		15,954,000
Mortgage loans held-for-sale	45,500,000		$ 31,800,000
Loans sold	193,800,000	247,100,000
Gain on mortgage loans sold, net	$ 4,878,000	$ 3,744,000
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of credit exposure to risk based capital	84.10%		85.20%
Non-owner occupied commercial real estate and multifamily loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of credit exposure to risk based capital	282.50%		277.70%