Loans and Allowance for Credit Losses on Loans - Balance in the Allowance for Loan Losses and the Recorded Investment in Loans by Portfolio Segment, Based on the Impairment Method (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance in the Allowance for Loan Losses and the Recorded Investment in Loans by Portfolio Segment, Based on the Impairment Method
Allowance for loan losses, Individually evaluated for impairment			$ 1,835
Allowance for loan losses, Collectively evaluated for impairment			21,450
Total allowance balance	$ 44,400	$ 31,855	23,285	$ 27,848	$ 19,658
Loans, Individually evaluated for impairment			10,264
Loans, Collectively evaluated for impairment			2,523,899
Total loan balance	$ 2,625,987	$ 31,855	2,534,163
Commercial
Balance in the Allowance for Loan Losses and the Recorded Investment in Loans by Portfolio Segment, Based on the Impairment Method
Allowance for loan losses, Individually evaluated for impairment			1,835
Allowance for loan losses, Collectively evaluated for impairment			8,618
Total allowance balance			10,453	17,061	10,608
Loans, Individually evaluated for impairment			4,810
Loans, Collectively evaluated for impairment			598,535
Total loan balance			603,345
Real estate
Balance in the Allowance for Loan Losses and the Recorded Investment in Loans by Portfolio Segment, Based on the Impairment Method
Allowance for loan losses, Collectively evaluated for impairment			12,750
Total allowance balance			12,750	10,671	8,950
Loans, Individually evaluated for impairment			5,454
Loans, Collectively evaluated for impairment			1,891,620
Total loan balance			1,897,074
Consumer
Balance in the Allowance for Loan Losses and the Recorded Investment in Loans by Portfolio Segment, Based on the Impairment Method
Allowance for loan losses, Collectively evaluated for impairment			82
Total allowance balance			82	$ 116	$ 100
Loans, Collectively evaluated for impairment			33,744
Total loan balance			$ 33,744