Disclosures About Fair Value of Assets and Liabilities - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets:
Investment securities available for sale	$ 742,759	$ 696,862
Investment securities held to maturity	609,256	611,933
Loans held for sale	4,036	2,929
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	142,650	127,927
Interest-bearing time deposits	48,305	24,459
Investment securities available for sale	33,300	18,765
Liabilities:
Deposits	4,724,324	4,427,605
Significant Other Observable Inputs (Level 2)
Assets:
Investment securities available for sale	706,129	672,928
Investment securities held to maturity	596,015	597,246
Loans held for sale	4,036	2,929
Federal Home Loan Bank stock	19,015	17,964
Interest rate swap and cap asset	6,123	6,310
Interest receivable	27,597	26,194
Liabilities:
Deposits	1,275,619	1,111,491
Borrowings:
Federal funds purchased	134,608	120,349
Securities sold under repurchase agreements	127,839	146,449
Federal Home Loan Bank advances	316,819	297,465
Subordinated debentures and term loans	106,962	105,930
Interest rate swap liability	8,234	8,477
Interest payable	3,477	3,110
Significant Unobservable Inputs (Level 3)
Assets:
Investment securities available for sale	3,330	5,169
Investment securities held to maturity	13,241	14,687
Loans	5,435,004	4,933,552
Carrying Amount
Assets:
Cash and cash equivalents	142,650	127,927
Interest-bearing time deposits	48,305	24,459
Investment securities available for sale	742,759	696,862
Investment securities held to maturity	600,564	607,643
Loans held for sale	4,036	2,929
Loans	5,542,673	5,073,608
Federal Home Loan Bank stock	19,015	17,964
Interest rate swap and cap asset	6,123	6,310
Interest receivable	27,597	26,194
Liabilities:
Deposits	6,017,104	5,556,498
Borrowings:
Federal funds purchased	134,608	120,349
Securities sold under repurchase agreements	127,884	146,480
Federal Home Loan Bank advances	312,715	298,923
Subordinated debentures and term loans	128,742	128,445
Interest rate swap liability	8,234	8,477
Interest payable	$ 3,477	$ 3,110

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Interest Bearing Deposits with Banks, Fair Value Disclosure

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Interest Payable Fair Value Disclosure

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Interest Receivable, Fair Value Disclosure

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. 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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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

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Fair value of investments in debt securities classified as held-to-maturity.

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Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The face amount of loans that will be sold to other entities.

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Fair value portion of other liabilities.

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Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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