Fair Value Measurements - (Details 7) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financial assets
Securities held to maturity	$ 470,597us-gaap_HeldToMaturitySecurities	$ 430,163us-gaap_HeldToMaturitySecurities
Securities available for sale	545,797us-gaap_AvailableForSaleSecurities	553,584us-gaap_AvailableForSaleSecurities
Mortgage loans held for sale	102,780us-gaap_LoansHeldForSaleMortgages	25,628us-gaap_LoansHeldForSaleMortgages
Loans covered under loss-share agreements	125,773	143,041
FDIC loss-share indemnification asset	8,934us-gaap_FDICIndemnificationAsset	12,516us-gaap_FDICIndemnificationAsset
Mortgage servicing rights	11,879us-gaap_ServicingAssetAtAmortizedValue	11,662us-gaap_ServicingAssetAtAmortizedValue
Carrying Value
Financial assets
Cash and cash equivalents	174,379	161,583
Securities held to maturity	470,597	430,163
Securities available for sale	545,797	553,584
Mortgage loans held for sale	102,780	25,628
Loans covered under loss-share agreements	125,773	143,041
Loans not covered under loss-share agreements, net	3,827,888	3,844,833
FDIC loss-share indemnification asset	8,934	12,516
Mortgage servicing rights	11,879	11,662
Derivative instruments	7,423	3,731
Financial liabilities
Deposits	4,942,769	4,838,418
Short-term borrowings	6,732	32,403
Federal Home Loan Bank advances	60,671	61,611
Junior subordinated debentures	94,684	94,574
Derivative instruments	8,938	6,293
Level 1
Financial assets
Cash and cash equivalents	174,379	161,583
Securities held to maturity	0	0
Securities available for sale	0	0
Mortgage loans held for sale	0	0
Loans covered under loss-share agreements	0	0
Loans not covered under loss-share agreements, net	0	0
FDIC loss-share indemnification asset	0	0
Mortgage servicing rights	0	0
Derivative instruments	0	0
Financial liabilities
Deposits	3,372,943	3,532,266
Short-term borrowings	6,732	32,403
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Derivative instruments	0	0
Level 2
Financial assets
Cash and cash equivalents	0	0
Securities held to maturity	486,624	442,488
Securities available for sale	525,671	533,828
Mortgage loans held for sale	102,780	25,628
Loans covered under loss-share agreements	0	0
Loans not covered under loss-share agreements, net	0	0
FDIC loss-share indemnification asset	0	0
Mortgage servicing rights	0	0
Derivative instruments	7,423	3,731
Financial liabilities
Deposits	1,227,259	1,309,421
Short-term borrowings	0	0
Federal Home Loan Bank advances	79,994	92,532
Junior subordinated debentures	80,971	80,971
Derivative instruments	8,938	6,293
Level 3
Financial assets
Cash and cash equivalents	0	0
Securities held to maturity	0	0
Securities available for sale	20,126	19,756
Mortgage loans held for sale	0	0
Loans covered under loss-share agreements	126,337	143,487
Loans not covered under loss-share agreements, net	3,745,570	3,751,727
FDIC loss-share indemnification asset	8,934	12,516
Mortgage servicing rights	12,213	12,378
Derivative instruments	0	0
Financial liabilities
Deposits	0	0
Short-term borrowings	0	0
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Derivative instruments	0	0
Fair Value
Financial assets
Cash and cash equivalents	174,379	161,583
Securities held to maturity	486,624	442,488
Securities available for sale	545,797	553,584
Mortgage loans held for sale	102,780	25,628
Loans covered under loss-share agreements	126,337	143,487
Loans not covered under loss-share agreements, net	3,745,570	3,751,727
FDIC loss-share indemnification asset	8,934	12,516
Mortgage servicing rights	12,213	12,378
Derivative instruments	7,423	3,731
Financial liabilities
Deposits	4,600,202	4,841,687
Short-term borrowings	6,732	32,403
Federal Home Loan Bank advances	79,994	92,532
Junior subordinated debentures	80,971	80,971
Derivative instruments	$ 8,938	$ 6,293

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

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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 of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

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Carrying amount of receivable assets originating from the indemnification agreement with the Federal Deposit Insurance Corporation (FDIC), in which the FDIC is to partially cover losses.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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