Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 9,900,000	$ 1,900,000
Commitments outstanding on troubled debt restructurings	500,000		$ 500,000
Recorded investment in troubled debt restructurings that subsequently defaulted within twelve months	0	0
Reserve for unfunded commitments	1,400,000		$ 1,200,000
Provisions for (credits to) unfunded commitments	198,000	(156,000)
Charge-offs or recoveries related to reserve for unfunded commitments	0	0
Acquired Impaired Loans
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	1,500,000	111,000
Individually Evaluated For Impairment
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	2,700,000	910,000
Collectively Evaluated For Impairment
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 5,600,000	$ 884,000