Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Loans and Allowance for Loan Losses - Summary of Loan Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 1,074,202		$ 947,882
Less net unearned income	(332)		(345)
Total loans	1,073,870		947,537
Less allowance for loan losses	(15,218)	$ (14,705)	(13,721)	$ (14,122)	$ (12,454)	$ (11,634)
Loans, net	1,058,652		933,816
Commercial real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	404,753		350,622
Less allowance for loan losses	(3,145)	(3,551)	(3,324)	(3,294)	(3,533)	(2,655)
Consumer real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	112,957		102,581
Less allowance for loan losses	(983)	(1,057)	(1,063)	(984)	(1,081)	(1,013)
Construction and land development
Loans And Leases Receivable Disclosure [Line Items]
Total loans	129,799		82,586
Less allowance for loan losses	(2,213)	(1,764)	(1,628)	(1,487)	(911)	(1,574)
Commercial and industrial
Loans And Leases Receivable Disclosure [Line Items]
Total loans	398,626		373,248
Less allowance for loan losses	(8,568)	(7,779)	(7,209)	(7,949)	(6,395)	(5,618)
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Total loans	8,274		6,862
Less allowance for loan losses	(93)	(120)	(91)	(79)	(57)	(76)
Other
Loans And Leases Receivable Disclosure [Line Items]
Total loans	19,793		31,983
Less allowance for loan losses	$ (216)	$ (434)	$ (406)	$ (329)	$ (477)	$ (698)