Loans and Leases and Allowance for Credit Losses - Average balances of impaired loans and income recognized on impaired loans (Details) - Loans Receivable - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Average balances of impaired loans and income recognized on impaired loans
Average Balance	$ 59,748	$ 78,354	$ 90,425
Interest Revenue Recognized During Impairment	3,084	3,632	4,274
Cash Basis Interest Revenue Received	3,124	3,592	4,338
Home equity lines of credit
Average balances of impaired loans and income recognized on impaired loans
Average Balance	284	248	93
Interest Revenue Recognized During Impairment	18	10	4
Cash Basis Interest Revenue Received	16	12	4
Indirect auto
Average balances of impaired loans and income recognized on impaired loans
Average Balance	1,252	1,244	928
Interest Revenue Recognized During Impairment	64	64	47
Cash Basis Interest Revenue Received	64	64	47
Commercial
Average balances of impaired loans and income recognized on impaired loans
Average Balance	42,043	60,731	73,307
Interest Revenue Recognized During Impairment	2,247	2,886	3,475
Cash Basis Interest Revenue Received	2,288	2,825	3,543
Commercial \| Owner occupied commercial real estate
Average balances of impaired loans and income recognized on impaired loans
Average Balance	19,881	27,870	33,297
Interest Revenue Recognized During Impairment	1,078	1,271	1,667
Cash Basis Interest Revenue Received	1,119	1,291	1,704
Commercial \| Income producing commercial real estate
Average balances of impaired loans and income recognized on impaired loans
Average Balance	17,138	24,765	31,661
Interest Revenue Recognized During Impairment	893	1,265	1,418
Cash Basis Interest Revenue Received	895	1,178	1,457
Commercial \| Construction
Average balances of impaired loans and income recognized on impaired loans
Average Balance	3,247	5,102	5,879
Interest Revenue Recognized During Impairment	176	225	267
Cash Basis Interest Revenue Received	174	229	264
Commercial \| Equipment financing
Average balances of impaired loans and income recognized on impaired loans
Average Balance	0	0	0
Interest Revenue Recognized During Impairment	0	0	0
Cash Basis Interest Revenue Received	0	0	0
Commercial \| Commercial & industrial
Average balances of impaired loans and income recognized on impaired loans
Average Balance	1,777	2,994	2,470
Interest Revenue Recognized During Impairment	100	125	123
Cash Basis Interest Revenue Received	100	127	118
Residential \| Construction
Average balances of impaired loans and income recognized on impaired loans
Average Balance	1,405	1,582	1,677
Interest Revenue Recognized During Impairment	96	95	89
Cash Basis Interest Revenue Received	95	95	88
Residential \| Residential mortgage
Average balances of impaired loans and income recognized on impaired loans
Average Balance	14,515	14,257	14,118
Interest Revenue Recognized During Impairment	641	555	637
Cash Basis Interest Revenue Received	643	574	633
Consumer direct
Average balances of impaired loans and income recognized on impaired loans
Average Balance	249	292	302
Interest Revenue Recognized During Impairment	18	22	22
Cash Basis Interest Revenue Received	$ 18	$ 22	$ 23

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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+ References

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