Disclosures About Fair Value of Assets and Liabilities - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets:
Investment securities available for sale	$ 658,829	$ 658,400
Investment securities held to maturity	665,066	632,380
Loans held for sale	18,854	9,894
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	120,471	102,170
Interest-bearing time deposits	62,533	32,315
Liabilities:
Deposits	4,268,709	4,095,004
Significant Other Observable Inputs (Level 2)
Assets:
Investment securities available for sale	653,265	652,468
Investment securities held to maturity	648,705	598,082
Loans held for sale	18,854	9,894
Federal Reserve Bank and Federal Home Loan Bank stock	18,096	37,633
Interest rate swap and cap asset	11,976	4,974
Interest receivable	23,351	24,415
Liabilities:
Deposits	1,129,241	1,177,142
Borrowings:
Federal funds purchased	20,000	49,721
Securities sold under repurchase agreements	140,763	155,325
Federal Home Loan Bank advances	268,150	236,375
Subordinated debentures and term loans	103,155	103,643
Interest rate swap liability	17,761	8,070
Interest payable	3,051	3,092
Significant Unobservable Inputs (Level 3)
Assets:
Investment securities available for sale	5,564	5,932
Investment securities held to maturity	16,361	34,298
Loans	4,710,073	4,539,940
Carrying Amount
Assets:
Cash and cash equivalents	120,471	102,170
Interest-bearing time deposits	62,533	32,315
Investment securities available for sale	658,829	658,400
Investment securities held to maturity	638,972	618,599
Loans held for sale	18,854	9,894
Loans	4,729,243	4,631,369
Federal Reserve Bank and Federal Home Loan Bank stock	18,096	37,633
Interest rate swap and cap asset	11,976	4,974
Interest receivable	23,351	24,415
Liabilities:
Deposits	5,407,554	5,289,647
Borrowings:
Federal funds purchased	20,000	49,721
Securities sold under repurchase agreements	140,777	155,325
Federal Home Loan Bank advances	268,579	235,652
Subordinated debentures and term loans	127,678	127,846
Interest rate swap liability	17,761	8,070
Interest payable	$ 3,051	$ 3,092

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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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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
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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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