Loans and Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 12,454	$ 10,454	$ 11,634	$ 10,132
Charged-off loans		(645)	(12,369)	(1,452)
Recoveries	1,863	62	1,957	71
Provision for loan losses	(195)	1,639	12,900	2,759
Ending Balance	14,122	11,510	14,122	11,510
Commercial real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	3,533	2,596	2,655	2,879
Charged-off loans				(350)
Recoveries	3	52	4	52
Provision for loan losses	(242)	(228)	635	(161)
Ending Balance	3,294	2,420	3,294	2,420
Consumer real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,081	968	1,013	968
Provision for loan losses	(97)	4	(29)	4
Ending Balance	984	972	984	972
Construction and land development
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	911	943	1,574	914
Provision for loan losses	576	721	(87)	750
Ending Balance	1,487	1,664	1,487	1,664
Commercial and industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	6,395	5,037	5,618	4,693
Charged-off loans		(645)	(12,369)	(956)
Recoveries	1,860	10	1,862	18
Provision for loan losses	(306)	1,166	12,838	1,813
Ending Balance	7,949	5,568	7,949	5,568
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	57	104	76	103
Charged-off loans				(146)
Recoveries			91	1
Provision for loan losses	22	(18)	(88)	128
Ending Balance	79	86	79	86
Other
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	477	806	698	575
Provision for loan losses	(148)	(6)	(369)	225
Ending Balance	$ 329	$ 800	$ 329	$ 800