Loans and Allowance - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Receivables [Abstract]
Loans held for sale	$ 18,582,000		$ 18,582,000				$ 3,966,000
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,121,250,000		9,121,250,000				9,243,174,000
Interest income recognized on non-accrual loans	$ 0	$ 0	$ 0	$ 0
Standby letters of credit usual term	2 years		2 years
Allowance for credit losses on unfunded loan commitments	$ 20,500,000		$ 20,500,000		$ 20,500,000		0
Cumulative effect of ASC 326 adoption
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans						$ 4,776,000
Allowance for credit losses on unfunded loan commitments	20,500,000		20,500,000			$ 20,500,000
30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	13,007,000		13,007,000				19,638,000
Increase (decrease) in past due loans			6,600,000
Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	68,400,000		68,400,000				72,800,000
Increase (decrease) in past due loans			4,400,000
PPP loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	415,800,000		415,800,000				667,100,000
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 1,127,442,000		$ 1,127,442,000				1,234,741,000
Percentage of troubled debt restructured loans	7600.00%		6500.00%
Mortgage loans with formal foreclosure proceedings	$ 3,200,000	$ 492,000	$ 3,200,000	$ 492,000
Residential | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 2,276,000		$ 2,276,000				$ 3,269,000