Business Combinations Consideration, Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands		12 Months Ended
Mar. 04, 2015	Dec. 31, 2015	Dec. 31, 2014
Fair Value of Liabilities Assumed
Goodwill		$ 291,764	$ 175,820
Integrity Bancshares, Inc.
Business Acquisition [Line Items]
Cash	$ 29,500	29,510
Common stock		142,469
Fair Value of Total Consideration	172,000	171,979
Fair Value of Assets Acquired
Cash and cash equivalents		13,163
Securities and other investments		11,502
Loans	788,700	788,687
Bank owned life insurance		15,974
Premises and equipment		10,855
Core deposit intangible		5,713
Other assets		18,994
Total Assets Acquired		864,888
Fair Value of Liabilities Assumed
Deposits		722,308
Borrowings		82,286
Other liabilities		4,259
Total Liabilities Assumed		808,853
Total Fair Value of Identifiable Net Assets		56,035
Goodwill	$ 115,900	$ 115,944

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Bank Owned Life Insurance

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Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits

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Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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 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.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of assets acquired at the acquisition date.

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Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of investments in debt and equity securities, including, but not limited to, held-to-maturity, trading and available-for-sale expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Amount of liabilities assumed at the acquisition date.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of other liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.

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The amount of property, plant, and equipment recognized as of the acquisition date.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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