Loans - (Impaired Loans - Average Recorded Investment and Interest Income Recognized) (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015
Loans [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 48,983	$ 41,968
Impaired Financing Receivable, Interest Income, Cash Basis Method	317	528
Commercial and Industrial [Member]
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	4,564	16,138
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	138	357
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	4,312	1,549
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method		1
Owner-Occupied [Member]
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	1,869	1,910
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	49	35
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	865	960
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	7	13
Agriculture [Member]
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	1,758
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	179	407
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	3	2
Energy Loans [Member]
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		12,532
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	26,005
Commercial Loan [Member]
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	8,191	30,580
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	187	392
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	31,361	2,916
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	10	16
Multifamily [Member]
Loans [Line Items]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	36	39
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	1
Non Owner-Occupied [Member]
Loans [Line Items]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	823	863
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	24	26
Total Commercial Real Estate [Member]
Loans [Line Items]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	859	902
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	25	26
Senior lien
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	1,312	315
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	14	9
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	5,212	5,880
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	53	59
Junior lien
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	136
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	1
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	1,670	1,326
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	27	26
Residential Real Estate Segment [Member]
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	1,448	315
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	15	9
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	6,882	7,206
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	80	85
Consumer [Member]
Loans [Line Items]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	242	49
Impaired Loans With No Related Allowance Recorded [Member] [Member]
Loans [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	9,639	30,895
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	202	401
Impaired Loans with Related Allowance Recorded [Member]
Loans [Line Items]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	39,344	11,073
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	$ 115	$ 127

Loans [Line Items]

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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=49124121&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=49124121&loc=d3e5258-111524

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- Definition

Amount of interest income recognized on a cash-basis method of accounting 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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- Definition

Amount of average investment of impaired financing receivables for which there is no 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 17
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5258-111524

Reference 2: 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=49124121&loc=d3e5212-111524

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- Definition

Amount of interest income, recognized on cash basis, on financing receivables, for which there is no related allowance for credit losses and are recognized as impaired.

+ References

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- Definition

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+ References

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- Definition

Amount of interest income on financing receivables, for which there is a related allowance for credit losses, recognized on a cash-basis method of accounting that the financing receivables were impaired.

+ References

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