Allowance For Credit Losses for Loans - Prior Period Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses [Line Items]
Adversely classified loans to total loans			1.79%
The ratio of non-accrual loans to total loans	1.15%		1.24%
Total recorded investment in impaired loans	$ 44,254,000		$ 48,318,000
Total non accruing impaired loans	34,900,000		10,300,000
Impaired non-accrual loans			38,000,000.0
Total troubled debt restructure (TDR) loans	17,500,000		17,700,000
TDR loans on accrual status	9,500,000		10,300,000
TDR loans included in non-performing loans	8,000,000.0		7,500,000
Charge-offs associated with new TDRs	$ 0	$ 0
Allowance for loan losses		$ 39,764,000	$ 44,565,000	$ 33,614,000
Allowance for loan losses to total loans ratio		1.48%	1.45%
Pass
Financing Receivable, Allowance for Credit Losses [Line Items]
Non-accrual loans not adversely classified			$ 137,000