Loans and Allowance for Loan and Lease Losses - Credit Quality (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Non-PCI loans by the internal risk grading system
Total Gross loans	$ 1,385,462	$ 1,247,280
Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	1,328,369	1,190,282
Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	15,934	12,048
Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	41,159	44,950
Real Estate Secured
Non-PCI loans by the internal risk grading system
Total Gross loans	1,130,064	1,012,076
Real Estate Secured | Commercial
Non-PCI loans by the internal risk grading system
Total Gross loans	643,691	579,244
Real Estate Secured | Residential 1 to 4 family
Non-PCI loans by the internal risk grading system
Total Gross loans	205,999	165,829
Real Estate Secured | Farmland
Non-PCI loans by the internal risk grading system
Total Gross loans	155,771	120,566
Real Estate Secured | Multi-family residential
Non-PCI loans by the internal risk grading system
Total Gross loans	77,941	79,381
Real Estate Secured | Construction and land
Non-PCI loans by the internal risk grading system
Total Gross loans	21,866	35,669
Real Estate Secured | Home equity lines of credit
Non-PCI loans by the internal risk grading system
Total Gross loans	24,796	31,387
Commercial
Non-PCI loans by the internal risk grading system
Total Gross loans	251,202	229,171
Commercial | Commercial and industrial
Non-PCI loans by the internal risk grading system
Total Gross loans	182,637	164,808
Commercial | Agriculture
Non-PCI loans by the internal risk grading system
Total Gross loans	68,565	64,363
Consumer
Non-PCI loans by the internal risk grading system
Total Gross loans	4,196	6,033
Non-PCI Loans
Non-PCI loans by the internal risk grading system
Total Gross loans	1,377,570	1,238,505
Non-PCI Loans | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	1,327,329	1,189,524
Non-PCI Loans | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	12,518	10,819
Non-PCI Loans | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	37,723	38,162
Non-PCI Loans | Real Estate Secured
Non-PCI loans by the internal risk grading system
Total Gross loans	1,124,114	1,005,536
Non-PCI Loans | Real Estate Secured | Commercial
Non-PCI loans by the internal risk grading system
Total Gross loans	638,089	573,559
Non-PCI Loans | Real Estate Secured | Commercial | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	612,600	545,614
Non-PCI Loans | Real Estate Secured | Commercial | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	9,489	4,402
Non-PCI Loans | Real Estate Secured | Commercial | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	16,000	23,543
Non-PCI Loans | Real Estate Secured | Residential 1 to 4 family
Non-PCI loans by the internal risk grading system
Total Gross loans	205,875	165,256
Non-PCI Loans | Real Estate Secured | Residential 1 to 4 family | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	205,173	164,226
Non-PCI Loans | Real Estate Secured | Residential 1 to 4 family | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	216	405
Non-PCI Loans | Real Estate Secured | Residential 1 to 4 family | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	486	625
Non-PCI Loans | Real Estate Secured | Farmland
Non-PCI loans by the internal risk grading system
Total Gross loans	155,771	120,566
Non-PCI Loans | Real Estate Secured | Farmland | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	153,139	118,740
Non-PCI Loans | Real Estate Secured | Farmland | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	364	245
Non-PCI Loans | Real Estate Secured | Farmland | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	2,268	1,581
Non-PCI Loans | Real Estate Secured | Multi-family residential
Non-PCI loans by the internal risk grading system
Total Gross loans	77,941	79,381
Non-PCI Loans | Real Estate Secured | Multi-family residential | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	77,941	79,381
Non-PCI Loans | Real Estate Secured | Construction and land
Non-PCI loans by the internal risk grading system
Total Gross loans	21,642	35,387
Non-PCI Loans | Real Estate Secured | Construction and land | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	18,382	30,219
Non-PCI Loans | Real Estate Secured | Construction and land | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans		939
Non-PCI Loans | Real Estate Secured | Construction and land | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	3,260	4,229
Non-PCI Loans | Real Estate Secured | Home equity lines of credit
Non-PCI loans by the internal risk grading system
Total Gross loans	24,796	31,387
Non-PCI Loans | Real Estate Secured | Home equity lines of credit | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	24,618	31,103
Non-PCI Loans | Real Estate Secured | Home equity lines of credit | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	178	284
Non-PCI Loans | Commercial
Non-PCI loans by the internal risk grading system
Total Gross loans	249,260	226,936
Non-PCI Loans | Commercial | Commercial and industrial
Non-PCI loans by the internal risk grading system
Total Gross loans	182,165	164,025
Non-PCI Loans | Commercial | Commercial and industrial | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	171,888	152,979
Non-PCI Loans | Commercial | Commercial and industrial | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	5	4,730
Non-PCI Loans | Commercial | Commercial and industrial | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	10,272	6,316
Non-PCI Loans | Commercial | Agriculture
Non-PCI loans by the internal risk grading system
Total Gross loans	67,095	62,911
Non-PCI Loans | Commercial | Agriculture | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	59,481	61,340
Non-PCI Loans | Commercial | Agriculture | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	2,444	98
Non-PCI Loans | Commercial | Agriculture | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	5,170	1,473
Non-PCI Loans | Consumer
Non-PCI loans by the internal risk grading system
Total Gross loans	4,196	6,033
Non-PCI Loans | Consumer | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	4,107	5,922
Non-PCI Loans | Consumer | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	89	111
PCI loans
Non-PCI loans by the internal risk grading system
Total Gross loans	7,892	8,775
PCI loans | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	1,040	758
PCI loans | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	3,416	1,229
PCI loans | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	3,436	6,788
PCI loans | Real Estate Secured
Non-PCI loans by the internal risk grading system
Total Gross loans	5,950	6,540
PCI loans | Real Estate Secured | Commercial
Non-PCI loans by the internal risk grading system
Total Gross loans	5,602	5,685
PCI loans | Real Estate Secured | Commercial | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	766
PCI loans | Real Estate Secured | Commercial | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	2,921	1,094
PCI loans | Real Estate Secured | Commercial | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	1,915	4,591
PCI loans | Real Estate Secured | Residential 1 to 4 family
Non-PCI loans by the internal risk grading system
Total Gross loans	124	573
PCI loans | Real Estate Secured | Residential 1 to 4 family | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans		455
PCI loans | Real Estate Secured | Residential 1 to 4 family | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	124
PCI loans | Real Estate Secured | Residential 1 to 4 family | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans		118
PCI loans | Real Estate Secured | Construction and land
Non-PCI loans by the internal risk grading system
Total Gross loans	224	282
PCI loans | Real Estate Secured | Construction and land | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	224	228
PCI loans | Real Estate Secured | Construction and land | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans		54
PCI loans | Real Estate Secured | Commercial and industrial
Non-PCI loans by the internal risk grading system
Total Gross loans		783
PCI loans | Real Estate Secured | Agriculture
Non-PCI loans by the internal risk grading system
Total Gross loans		1,452
PCI loans | Commercial
Non-PCI loans by the internal risk grading system
Total Gross loans	1,942	2,235
PCI loans | Commercial | Commercial and industrial
Non-PCI loans by the internal risk grading system
Total Gross loans	472	783
PCI loans | Commercial | Commercial and industrial | Credit Risk Grades, Pass
Non-PCI loans by the internal risk grading system
Total Gross loans	50	75
PCI loans | Commercial | Commercial and industrial | Credit Risk Grades, Special Mention
Non-PCI loans by the internal risk grading system
Total Gross loans	371	81
PCI loans | Commercial | Commercial and industrial | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	51	627
PCI loans | Commercial | Agriculture
Non-PCI loans by the internal risk grading system
Total Gross loans	1,470	1,452
PCI loans | Commercial | Agriculture | Credit Risk Grades, Substandard
Non-PCI loans by the internal risk grading system
Total Gross loans	$ 1,470	$ 1,452