Summary of Significant Accounting Policies - Business Combinations and Method of Accounting for Loans Acquired - (Details)	Dec. 31, 2016 USD ($)
Business Combinations, Method of Accounting for Loans Acquired, and FDIC Indemnification Asset
Allowance for loan losses on acquired loans	$ 0
CBT
Business Combinations, Method of Accounting for Loans Acquired, and FDIC Indemnification Asset
Minimum amount of commercial loans included in loan categories with common risk categories	1,000,000
Minimum amount of outstanding contractual principal balances of commercial loans included in loan categories with common risk categories	$ 1,000,000

Reserve for loans impairments recorded after acquisition as a result of current information and events which result in it being probable that estimated cash flows will be less than previously expected or because actual cash flows are less than cash flows previously expected. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant