Loans and Allowance for Loan Losses (Troubled Debt Restructurings Modified by Portfolio Class) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) contract	Dec. 31, 2016 USD ($) contract	Dec. 31, 2015 USD ($) contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	78	47	7
Pre-Modification Outstanding Recorded Investment	$ 177,070	$ 132,234	$ 5,120
Post-Modification Outstanding Recorded Investment	$ 177,070	$ 132,234	$ 5,107
Total Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	57	39	1
Pre-Modification Outstanding Recorded Investment	$ 168,593	$ 128,597	$ 4,420
Post-Modification Outstanding Recorded Investment	$ 168,593	$ 128,597	$ 4,420
Total Commercial [Member] \| Commercial Real Estate - Income Producing [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	5	1	1
Pre-Modification Outstanding Recorded Investment	$ 5,625	$ 2,943	$ 485
Post-Modification Outstanding Recorded Investment	$ 5,625	$ 2,943	$ 482
Residential Mortgages [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	15	7	4
Pre-Modification Outstanding Recorded Investment	$ 2,812	$ 694	$ 195
Post-Modification Outstanding Recorded Investment	$ 2,812	$ 694	$ 185
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	1		1
Pre-Modification Outstanding Recorded Investment	$ 40		$ 20
Post-Modification Outstanding Recorded Investment	$ 40		$ 20
Total Commercial And Industrial [Member] \| Total Commercial [Member] \| Commercial Non-Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	52	38	1
Pre-Modification Outstanding Recorded Investment	$ 162,909	$ 128,449	$ 4,420
Post-Modification Outstanding Recorded Investment	$ 162,909	$ 128,449	$ 4,420
Total Commercial And Industrial [Member] \| Total Commercial [Member] \| Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	5	1
Pre-Modification Outstanding Recorded Investment	$ 5,684	$ 148
Post-Modification Outstanding Recorded Investment	$ 5,684	$ 148

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

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