Premises and Equipment and Leases - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2020
Property Plant And Equipment [Line Items]
Depreciation	$ 6,512,000	$ 4,231,000	$ 3,688,000
Operating Lease, Right-of-Use Asset	$ 16,900,000	$ 8,900,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Operating Lease, Liability	$ 17,766,000	$ 9,500,000
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities
Option extensions	true
Operating lease, option to extend	options for multiple five and ten year extensions
Operating lease, weighted average remaining lease term	15 years 1 month 2 days	17 years 25 days
Operating Lease, Weighted Average Discount Rate, Percent	2.61%	3.17%
Operating Lease, Cost	$ 2,300,000	$ 945,000
Rent expense for operating leases			$ 1,000,000.0
Minimum [Member]
Property Plant And Equipment [Line Items]
Lessee, Operating Lease, Renewal Term	5 years
Maximum [Member]
Property Plant And Equipment [Line Items]
Lessee, Operating Lease, Renewal Term	10 years
United Community Financial Corp
Property Plant And Equipment [Line Items]
Operating Lease, Right-of-Use Asset				$ 5,000,000.0
Operating Lease, Liability				$ 5,100,000