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	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
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	$ 44,703	$ 31,855	23,285
Loans, Individually evaluated for impairment			10,264
Loans, Collectively evaluated for impairment			2,523,899
Total loan balance	2,554,169		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
Loans, Individually evaluated for impairment			4,810
Loans, Collectively evaluated for impairment			626,737
Total loan balance	$ 682,280		631,547
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	$ 11,671	$ 10,671
Loans, Individually evaluated for impairment			5,454
Loans, Collectively evaluated for impairment			1,877,280
Total loan balance			1,882,734
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	$ 90	$ 116
Loans, Collectively evaluated for impairment			19,882
Total loan balance			$ 19,882