Loans, Troubled Debt Restructurings Subsequent Default (Details)	12 Months Ended
Dec. 31, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan	Dec. 31, 2015 USD ($) loan
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	66	68	91
Recorded Investment \| $	$ 3,879	$ 4,574	$ 8,232
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	2	0	2
Recorded Investment \| $	$ 0	$ 0	$ 197
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	36	44	61
Recorded Investment \| $	$ 3,137	$ 4,102	$ 6,815
Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	27	23	28
Recorded Investment \| $	$ 735	$ 457	$ 1,220
Other consumer
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	1	1	0
Recorded Investment \| $	$ 7	$ 15	$ 0

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

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- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

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