Employee Benefit Plans (Textual) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) plan shares	Dec. 31, 2018 USD ($) shares
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation arrangements, overall, description	After one year of service the Company matches 100% of employee contributions up to 3% of compensation and 50% of employee contributions on the next 2% of compensation.
Number of stock option plans | plan	1
Options vested in period, fair value	$ 317	$ 244
Deferred tax expense from stock options exercised	61	319
Options, exercises in period, intrinsic value	372	$ 1,500
Options, outstanding, intrinsic value	1,800
Options, exercisable, intrinsic value	1,800
Proceeds from stock options exercised	$ 374
Number of shares granted (in shares) | shares	0	0
Vested (in shares) | shares		0
Director [Member]
Defined Benefit Plan Disclosure [Line Items]
Direct stock grant expense	$ 65	$ 9
Deferred Salary Reduction Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost recognized	818	716
Stock Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based compensation expense	121	134
Stock Appreciation Rights (SARs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based compensation expense	134	34
Restricted Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based compensation expense	396	$ 263
Unrecognized compensation cost	$ 844
Unrecognized compensation costs, period for recognition	3 years 2 months 4 days
Grant-date fair value	$ 63
Vested (in shares) | shares	3,000
2015 Stock Incentive Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Rights issued (in shares) | shares	33,059
Rights available for grant (in shares) | shares	1,916,507
Cornerstone Bancshares, Inc. Long-Term Incentive Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Rights issued (in shares) | shares	38,250
Cornerstone Non-Qualified Plan Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Rights issued (in shares) | shares	51,750
Capstone Stock Option Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Rights issued (in shares) | shares	13,599
401 (k) Matching Range One [Member] | Deferred Salary Reduction Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Request service period	1 year
Employer matching contribution, percent of match	100.00%
Employer matching contribution, percent of employees gross pay	3.00%
401 (k) Matching Range Two [Member] | Deferred Salary Reduction Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of match	50.00%
Employer matching contribution, percent of employees gross pay	2.00%