Fair Value Accounting and Measurement (Carrying Amounts and Estimated Fair Values of Selected Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets
Interest-earning deposits with banks	$ 270,873	$ 202,925
Securities available for sale	997,763	1,028,110
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Assets
Cash and due from banks	98,940	91,364
Interest-earning deposits with banks	270,873	202,925
Securities available for sale	997,763	1,028,110
FHLB stock	22,215	22,215
Loans held for sale	2,088	2,148
Loans	2,847,759	2,827,259
FDIC loss-sharing asset	140,003	175,071
Interest rate contracts	16,408	16,302
Liabilities
Deposits	3,830,817	3,815,529
FHLB Advances	113,145	119,009
Repurchase agreements	25,000	25,000
Interest rate contracts	16,408	16,302
Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	98,940	91,364
Interest-earning deposits with banks	270,873	202,925
Securities available for sale	997,763	1,028,110
FHLB stock	22,215	22,215
Loans held for sale	2,088	2,148
Loans	2,962,261	2,957,345
FDIC loss-sharing asset	54,242	71,788
Interest rate contracts	16,408	16,302
Liabilities
Deposits	3,854,612	3,817,013
FHLB Advances	113,429	119,849
Repurchase agreements	26,354	26,580
Interest rate contracts	16,408	16,302
Fair Value, Inputs, Level 1 [Member] \| Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	98,940
Interest-earning deposits with banks	270,873
Securities available for sale	0
FHLB stock	0
Loans held for sale	0
Loans	0
FDIC loss-sharing asset	0
Interest rate contracts	0
Liabilities
Deposits	3,314,589
FHLB Advances	0
Repurchase agreements	0
Interest rate contracts	0
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	0
Interest-earning deposits with banks	0
Securities available for sale	997,763
FHLB stock	22,215
Loans held for sale	2,088
Loans	0
FDIC loss-sharing asset	0
Interest rate contracts	16,408
Liabilities
Deposits	540,023
FHLB Advances	113,429
Repurchase agreements	26,354
Interest rate contracts	16,408
Fair Value, Inputs, Level 3 [Member] \| Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	0
Interest-earning deposits with banks	0
Securities available for sale	0
FHLB stock	0
Loans held for sale	0
Loans	2,962,261
FDIC loss-sharing asset	54,242
Interest rate contracts	0
Liabilities
Deposits	0
FHLB Advances	0
Repurchase agreements	0
Interest rate contracts	$ 0

FDIC Loss Sharing Asset Fair Value Disclosure

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

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-Publisher FASB

-Name Accounting Standards Codification

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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-SubTopic 210

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-Name Regulation S-X (SX)

-Number 210

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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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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 4

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-Topic 310

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- Definition

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