Business Combinations and Divestitures - Summary of Non-Purchase credit Impaired Loans Acquired in Business Combination (Details) (NBI Acquisition, USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Contractual Balance	$ 562,658
Fair Value	545,246	568,358
Estimated Contractual Cash Flow Not Expected to be Collected	(15,298)
Commercial real estate
Business Acquisition [Line Items]
Contractual Balance	223,477
Fair Value	217,711
Estimated Contractual Cash Flow Not Expected to be Collected	(6,567)
Construction, land development, land
Business Acquisition [Line Items]
Contractual Balance	25,844
Fair Value	23,474
Estimated Contractual Cash Flow Not Expected to be Collected	(1,585)
1-4 family residential properties
Business Acquisition [Line Items]
Contractual Balance	93,868
Fair Value	89,822
Estimated Contractual Cash Flow Not Expected to be Collected	(2,520)
Farmland
Business Acquisition [Line Items]
Contractual Balance	35,502
Fair Value	35,634
Estimated Contractual Cash Flow Not Expected to be Collected	(74)
Commercial Loans
Business Acquisition [Line Items]
Contractual Balance	170,070
Fair Value	164,855
Estimated Contractual Cash Flow Not Expected to be Collected	(3,914)
Consumer
Business Acquisition [Line Items]
Contractual Balance	13,897
Fair Value	13,750
Estimated Contractual Cash Flow Not Expected to be Collected	$ (638)

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For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the best estimate at the acquisition date of the contractual cash flows not expected to be collected, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(3)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

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- Definition

For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the fair value of the receivables acquired, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

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- Definition

For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the gross contractual amounts receivable, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(2)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

+ Details

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