Loans and Allowance for Loan Losses - Nonaccrual loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	$ 15,325	$ 14,760	$ 15,325	$ 14,760	$ 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	57,153	65,208	57,153	65,208	59,460
Recorded Investment With No Allowance	9,944	11,197	9,944	11,197	10,714
Gross Recorded Investment With Allowance	44,565	51,396	44,565	51,396	46,304
Total Recorded Investment	54,509	62,593	54,509	62,593	57,018
Related Allowance	1,384	1,829	1,384	1,829	1,628
Average Investment In Impaired Loans	55,391	64,645	55,764	63,008
Interest Income Recognized	572	520	1,253	1,248
Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	9,948	9,373	9,948	9,373	13,489
Commercial non-owner occupied real estate | Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	780	1,532	780	1,532	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	299	423	299	423	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	481	1,109	481	1,109	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	36,539	42,955	36,539	42,955	38,314
Recorded Investment With No Allowance	321	600	321	600	339
Gross Recorded Investment With Allowance	35,809	41,792	35,809	41,792	37,574
Total Recorded Investment	36,130	42,392	36,130	42,392	37,913
Related Allowance	715	846	715	846	788
Average Investment In Impaired Loans	37,194	44,295	37,021	42,811
Interest Income Recognized	310	298	791	810
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	187	1,505	187	1,505	1,157
Recorded Investment With No Allowance	85	831	85	831	536
Gross Recorded Investment With Allowance	16	517	16	517	489
Total Recorded Investment	101	1,348	101	1,348	1,025
Related Allowance	1	93	1	93	70
Average Investment In Impaired Loans	238	1,265	563	1,362
Interest Income Recognized	2	9	4	15
Commercial non-owner occupied real estate | Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,484	369	1,484	369	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	1,207	369	1,207	369	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	277		277		283
Commercial owner occupied real estate loan | Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	3,459	1,526	3,459	1,526	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	6,673	5,733	6,673	5,733	5,085
Recorded Investment With No Allowance	3,833	3,031	3,833	3,031	3,101
Gross Recorded Investment With Allowance	1,607	1,719	1,607	1,719	1,041
Total Recorded Investment	5,440	4,750	5,440	4,750	4,142
Related Allowance	33	44	33	44	27
Average Investment In Impaired Loans	4,830	5,164	4,791	5,196
Interest Income Recognized	94	72	161	147
Commercial owner occupied real estate loan | Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,108	885	1,108	885	1,470
Consumer loans | Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	8,428	8,773	8,428	8,773	9,442
Consumer loans | Non acquired non-accrual loans | Home equity loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,740	2,308	1,740	2,308	2,333
Consumer loans | Non acquired non-accrual loans | Consumer Owner Occupied Loans
Loans and Allowance for Loan Losses
Nonaccrual loans	6,688	6,465	6,688	6,465	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	2,566	3,256	2,566	3,256	2,953
Recorded Investment With No Allowance	1,084	1,146	1,084	1,146	1,129
Gross Recorded Investment With Allowance	1,352	1,998	1,352	1,998	1,697
Total Recorded Investment	2,436	3,144	2,436	3,144	2,826
Related Allowance	125	180	125	180	142
Average Investment In Impaired Loans	2,595	3,156	2,631	3,077
Interest Income Recognized	32	36	64	65
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	5,989	6,085	5,989	6,085	7,291
Recorded Investment With No Allowance	3,983	4,631	3,983	4,631	4,992
Gross Recorded Investment With Allowance	1,583	997	1,583	997	1,769
Total Recorded Investment	5,566	5,628	5,566	5,628	6,761
Related Allowance	35	30	35	30	41
Average Investment In Impaired Loans	6,226	5,561	6,164	5,630
Interest Income Recognized	44	44	93	87
Consumer loans | Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	4,722	6,370	4,722	6,370	8,376
Consumer loans | Acquired non-credit impaired non-accrual including restructured loans | Home equity loans
Loans and Allowance for Loan Losses
Nonaccrual loans	3,023	4,234	3,023	4,234	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	1,699	2,136	1,699	2,136	3,864
Commercial and industrial | Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	285	811	285	811	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	2,708	1,876	2,708	1,876	1,332
Recorded Investment With No Allowance	509	724	509	724	467
Gross Recorded Investment With Allowance	2,165	1,110	2,165	1,110	824
Total Recorded Investment	2,674	1,834	2,674	1,834	1,291
Related Allowance	394	485	394	485	416
Average Investment In Impaired Loans	1,994	1,756	1,982	1,495
Interest Income Recognized	66	19	86	36
Commercial and industrial | Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	964	101	964	101	1,296
Other income producing property | Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	351	323	351	323	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	2,333	3,473	2,333	3,473	3,117
Recorded Investment With No Allowance	129	234	129	234	150
Gross Recorded Investment With Allowance	1,935	3,006	1,935	3,006	2,722
Total Recorded Investment	2,064	3,240	2,064	3,240	2,872
Related Allowance	78	144	78	144	142
Average Investment In Impaired Loans	2,210	3,163	2,468	3,189
Interest Income Recognized	24	42	54	88
Other income producing property | Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	228	254	228	254	244
Consumer | Non acquired non-accrual loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,351	893	1,351	893	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	158	325	158	325	211
Gross Recorded Investment With Allowance	98	257	98	257	188
Total Recorded Investment	98	257	98	257	188
Related Allowance	3	7	3	7	2
Average Investment In Impaired Loans	104	285	144	248
Consumer | Acquired non-credit impaired non-accrual including restructured loans
Loans and Allowance for Loan Losses
Nonaccrual loans	1,442	1,394	$ 1,442	1,394	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	$ 671	$ 902	$ 671	$ 902	$ 648