Loans - Activity in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	$ 8,925	$ 8,645	$ 8,591	$ 7,981	$ 7,981
Charge-offs	(93)	(350)	(731)	(1,458)
Recoveries	189	108	861	1,880
Provision	0	0	300	0
Ending Balance	9,021	8,403	9,021	8,403	8,591
Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	1,185	1,036	648	1,117	1,117
Charge-offs	(20)	0	(38)	(357)
Recoveries	91	54	160	144
Provision	12	(121)	498	65
Ending Balance	1,268	969	1,268	969	648
Agriculture & AG RE
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	103	65	97	69	69
Charge-offs	0	0	0	0
Recoveries	0	2	55	2
Provision	5	(1)	(44)	(5)
Ending Balance	108	66	108	66	97
Construction, Land & Development
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	452	396	523	711	711
Charge-offs	0	0	0	(3)
Recoveries	4	16	28	43
Provision	152	66	57	(273)
Ending Balance	608	478	608	478	523
Commercial RE
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	5,243	5,185	5,681	3,999	3,999
Charge-offs	0	(24)	(520)	(639)
Recoveries	24	9	495	1,616
Provision	(234)	35	(623)	229
Ending Balance	5,033	5,205	5,033	5,205	5,681
1-4 Family Residential
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	1,933	1,951	1,628	2,075	2,075
Charge-offs	(73)	(325)	(170)	(455)
Recoveries	69	24	120	45
Provision	70	25	421	10
Ending Balance	1,999	1,675	1,999	1,675	1,628
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	9	12	14	10	10
Charge-offs	0	(1)	(3)	(4)
Recoveries	1	3	3	30
Provision	(5)	(4)	(9)	(26)
Ending Balance	$ 5	$ 10	$ 5	$ 10	$ 14