Fair Value Accounting and Measurement (Carrying Amounts and Estimated Fair Values of Selected Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Assets
Interest-earning deposits with banks	$ 38,302	$ 389,353
Securities available for sale	1,507,900	1,001,665
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Assets
Cash and due from banks	154,407	124,573
Interest-earning deposits with banks	38,302	389,353
Securities available for sale	1,507,900	1,001,665
FHLB stock	33,139	21,819
Loans held for sale	2,150	2,563
Loans	4,467,981	2,864,803
FDIC loss-sharing asset	67,374	96,354
Interest rate contracts	10,043	14,921
Liabilities
Deposits	5,747,861	4,042,085
FHLB Advances	179,680	6,644
Repurchase agreements	25,000	25,000
Interest rate contracts	10,043	14,921
Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	154,407	124,573
Interest-earning deposits with banks	38,302	389,353
Securities available for sale	1,507,900	1,001,665
FHLB stock	33,139	21,819
Loans held for sale	2,150	2,563
Loans	4,461,356	2,944,317
FDIC loss-sharing asset	17,627	26,543
Interest rate contracts	10,043	14,921
Liabilities
Deposits	5,747,569	4,043,221
FHLB Advances	178,517	5,894
Repurchase agreements	26,327	26,464
Interest rate contracts	10,043	14,921
Fair Value, Inputs, Level 1 [Member] \| Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	154,407	124,573
Interest-earning deposits with banks	38,302	389,353
Securities available for sale	20,359	19,828
FHLB stock	0	0
Loans held for sale	0	0
Loans	0	0
FDIC loss-sharing asset	0	0
Interest rate contracts	0	0
Liabilities
Deposits	5,189,020	3,549,821
FHLB Advances	0	0
Repurchase agreements	0	0
Interest rate contracts	0	0
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	0	0
Interest-earning deposits with banks	0	0
Securities available for sale	1,487,541	981,837
FHLB stock	33,139	21,819
Loans held for sale	2,150	2,563
Loans	0	0
FDIC loss-sharing asset	0	0
Interest rate contracts	10,043	14,921
Liabilities
Deposits	558,549	493,400
FHLB Advances	178,517	5,894
Repurchase agreements	26,327	26,464
Interest rate contracts	10,043	14,921
Fair Value, Inputs, Level 3 [Member] \| Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Cash and due from banks	0	0
Interest-earning deposits with banks	0	0
Securities available for sale	0	0
FHLB stock	0	0
Loans held for sale	0	0
Loans	4,461,356	2,944,317
FDIC loss-sharing asset	17,627	26,543
Interest rate contracts	0	0
Liabilities
Deposits	0	0
FHLB Advances	0	0
Repurchase agreements	0	0
Interest rate contracts	$ 0	$ 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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-URI http://asc.fasb.org/extlink&oid=6505594

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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 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

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-Name Accounting Standards Codification

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No definition available.

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-Number AAG-DEP

-Paragraph 17

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-Chapter 15

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 2

-Article 9

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-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.2)

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-Chapter 6

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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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-Number AAG-DEP

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-Publisher FASB

-Name Accounting Standards Codification

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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. The amount of securities that an institution sells and agrees to repurchase (seller-borrower) at a specified date for a specified price, net of any reductions or offsets. Most repurchase agreements involve obligations of the federal government or its agencies, but other financial instruments, such as commercial paper, banker's acceptances, and negotiable certificates of deposit (CDs), are sometimes used in repurchase agreements. A repurchase agreement is similar to the seller-borrower's borrowing funds equal to the sales price of the related securities with the securities as collateral. Maturities of such agreements are flexible and generally vary from one day to 270 days.

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-Number AAG-DEP

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