Loans and Allowance for Loan Losses - Nonaccrual loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	$ 15,414	$ 14,109	$ 14,827
Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	58,849	80,646	59,460
Recorded Investment With No Allowance	10,072	10,591	10,714
Gross Recorded Investment With Allowance	46,201	56,105	46,304
Total Recorded Investment	56,273	66,696	57,018
Related Allowance	1,599	1,712	1,628
Average Investment In Impaired Loans	56,645	65,061
Interest Income Recognized	681	728
Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	14,294	8,076	13,489
Commercial non-owner occupied real estate \| Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	919	1,674	1,255
Commercial non-owner occupied real estate \| Non acquired non-accrual loans \| Construction and land development
Loans and Allowance for Loan Losses
Nonaccrual loans	414	500	424
Commercial non-owner occupied real estate \| Non acquired non-accrual loans \| Other commercial non-owner occupied real estate
Loans and Allowance for Loan Losses
Nonaccrual loans	505	1,174	831
Commercial non-owner occupied real estate \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20 \| Construction and land development
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	38,668	50,399	38,314
Recorded Investment With No Allowance	343	476	339
Gross Recorded Investment With Allowance	37,914	45,722	37,574
Total Recorded Investment	38,257	46,198	37,913
Related Allowance	786	767	788
Average Investment In Impaired Loans	38,085	44,714
Interest Income Recognized	481	513
Commercial non-owner occupied real estate \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20 \| Other commercial non-owner occupied real estate
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	514	2,916	1,157
Recorded Investment With No Allowance	99	659	536
Gross Recorded Investment With Allowance	276	522	489
Total Recorded Investment	375	1,181	1,025
Related Allowance	60	110	70
Average Investment In Impaired Loans	700	1,278
Interest Income Recognized	2	5
Commercial non-owner occupied real estate \| Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,403	426	535
Commercial non-owner occupied real estate \| Acquired non-credit impaired non-accrual including restructured loans \| Construction and land development
Loans and Allowance for Loan Losses
Nonaccrual loans	1,114	426	252
Commercial non-owner occupied real estate \| Acquired non-credit impaired non-accrual including restructured loans \| Other commercial non-owner occupied real estate
Loans and Allowance for Loan Losses
Nonaccrual loans	289		283
Commercial owner occupied real estate loan \| Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,215	1,647	1,068
Commercial owner occupied real estate loan \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	5,158	8,972	5,085
Recorded Investment With No Allowance	3,130	3,273	3,101
Gross Recorded Investment With Allowance	1,090	2,305	1,041
Total Recorded Investment	4,220	5,578	4,142
Related Allowance	21	63	27
Average Investment In Impaired Loans	4,181	5,610
Interest Income Recognized	67	75
Commercial owner occupied real estate loan \| Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,664	178	1,470
Consumer loans \| Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	10,324	8,134	9,442
Consumer loans \| Non acquired non-accrual loans \| Home equity loans
Loans and Allowance for Loan Losses
Nonaccrual loans	2,666	2,593	2,333
Consumer loans \| Non acquired non-accrual loans \| Consumer Owner Occupied Loans
Loans and Allowance for Loan Losses
Nonaccrual loans	7,658	5,541	7,109
Consumer loans \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20 \| Home equity loans
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	2,885	3,855	2,953
Recorded Investment With No Allowance	1,136	1,105	1,129
Gross Recorded Investment With Allowance	1,618	2,063	1,697
Total Recorded Investment	2,754	3,168	2,826
Related Allowance	161	73	142
Average Investment In Impaired Loans	2,790	3,090
Interest Income Recognized	32	29
Consumer loans \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20 \| Consumer Owner Occupied Loans
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	7,462	7,245	7,291
Recorded Investment With No Allowance	5,223	4,332	4,992
Gross Recorded Investment With Allowance	1,662	1,161	1,769
Total Recorded Investment	6,885	5,493	6,761
Related Allowance	37	35	41
Average Investment In Impaired Loans	6,823	5,563
Interest Income Recognized	49	43
Consumer loans \| Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	8,443	5,358	8,376
Consumer loans \| Acquired non-credit impaired non-accrual including restructured loans \| Home equity loans
Loans and Allowance for Loan Losses
Nonaccrual loans	4,750	3,931	4,512
Consumer loans \| Acquired non-credit impaired non-accrual including restructured loans \| Consumer Owner Occupied Loans
Loans and Allowance for Loan Losses
Nonaccrual loans	3,693	1,427	3,864
Commercial and industrial \| Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	286	799	647
Commercial and industrial \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	1,357	2,679	1,332
Recorded Investment With No Allowance		634	467
Gross Recorded Investment With Allowance	1,315	1,043	824
Total Recorded Investment	1,315	1,677	1,291
Related Allowance	420	489	416
Average Investment In Impaired Loans	1,303	1,417
Interest Income Recognized	20	17
Commercial and industrial \| Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	915	138	1,296
Other income producing property \| Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	596	170	500
Other income producing property \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	2,605	3,793	3,117
Recorded Investment With No Allowance	141	112	150
Gross Recorded Investment With Allowance	2,216	2,974	2,722
Total Recorded Investment	2,357	3,086	2,872
Related Allowance	111	166	142
Average Investment In Impaired Loans	2,614	3,112
Interest Income Recognized	30	46
Other income producing property \| Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	205	325	244
Consumer \| Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,244	903	1,267
Consumer \| Impaired non-acquired and acquired loans accounted under FASB ASC topic 310-20
Loans and Allowance for Loan Losses
Unpaid Contractual Principal Balance	200	787	211
Gross Recorded Investment With Allowance	110	315	188
Total Recorded Investment	110	315	188
Related Allowance	3	9	2
Average Investment In Impaired Loans	149	277
Consumer \| Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	$ 1,664	1,651	1,568
Restructured loans \| ASC Topic 31020 Loans
Loans and Allowance for Loan Losses
Number of months generally required to return to accruing status	6 months
Restructured loans \| Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	$ 830	$ 782	$ 648

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