Significant Accounting Policies - Additional Information (Details) $ in Millions		1 Months Ended	12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 22, 2017	Dec. 31, 2018 operating_segment commercial_banking_centers traditional_bank_offices	Dec. 31, 2017 USD ($)
Accounting Policies [Line Items]
Number of operating segments | operating_segment			1
Number of traditional bank offices | traditional_bank_offices			51
Number of commercial banking centers | commercial_banking_centers			7
Reclassification of accumulated unrealized loss	$ 0.1
Modified loan terms			6 months
Number of days past due			90 days
Number of days past due, consumer loans			120 days
Net operating loss carryforward limit percentage		80.00%
Limitation of the deduction for net business interest expense, percentage of taxable income		30.00%
Tax cuts and jobs act of 2017, additional income tax expense				$ 8.6
Reclassification of disproportionate tax effects upon adoption of new accounting pronouncement				$ 0.7
Stock Option
Accounting Policies [Line Items]
Vesting period			5 years
Minimum | Core Deposits
Accounting Policies [Line Items]
Intangible assets, useful life			6 years
Maximum | Core Deposits
Accounting Policies [Line Items]
Intangible assets, useful life			8 years
Building | Minimum
Accounting Policies [Line Items]
Bank premises and equipment, useful life			25 years
Building | Maximum
Accounting Policies [Line Items]
Bank premises and equipment, useful life			40 years
Leasehold Improvements | Minimum
Accounting Policies [Line Items]
Bank premises and equipment, useful life			5 years
Leasehold Improvements | Maximum
Accounting Policies [Line Items]
Bank premises and equipment, useful life			25 years
Furniture and Equipment | Minimum
Accounting Policies [Line Items]
Bank premises and equipment, useful life			3 years
Furniture and Equipment | Maximum
Accounting Policies [Line Items]
Bank premises and equipment, useful life			12 years