Fair Value (Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) (USD $)
In Thousands, unless otherwise specified

Dec. 31, 2012

Dec. 31, 2011

Fair Value, Measurements, Recurring [Member]

Financial Assets:

Trading account assets

$ 2,300

$ 2,244

Customer interest rate swap agreement

496

211

Financial Liabilities:

Interest rate swap agreements

11,580

11,387

Fair Value, Measurements, Recurring [Member] | Obligations of states and political subdivisions [Member]

Financial Assets:

Securities available-for-sale

33,040

39,758

Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

358,148

376,934

Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

381,688

128,450

Fair Value, Measurements, Recurring [Member] | Private issue collateralized mortgage obligations [Member]

Financial Assets:

Securities available-for-sale

8,174

10,641

Fair Value, Measurements, Recurring [Member] | Obligations of U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

30,107

Fair Value, Measurements, Recurring [Member] | Equity securities [Member]

Financial Assets:

Securities available-for-sale

4,146

Readily Available Market Prices (Level 1) [Member]

Financial Assets:

Securities available-for-sale

Customer interest rate swap agreement

Financial Liabilities:

Interest rate swap agreements

Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]

Financial Assets:

Trading account assets

2,300

2,244

Customer interest rate swap agreement

Financial Liabilities:

Interest rate swap agreements

Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of states and political subdivisions [Member]

Financial Assets:

Securities available-for-sale

Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Private issue collateralized mortgage obligations [Member]

Financial Assets:

Securities available-for-sale

Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Equity securities [Member]

Financial Assets:

Securities available-for-sale

Observable Market Data (Level 2) [Member]

Financial Assets:

Securities available-for-sale

781,050

Customer interest rate swap agreement

496

Financial Liabilities:

Interest rate swap agreements

11,580

Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]

Financial Assets:

Trading account assets

Customer interest rate swap agreement

496

211

Financial Liabilities:

Interest rate swap agreements

11,580

11,387

Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of states and political subdivisions [Member]

Financial Assets:

Securities available-for-sale

33,040

39,758

Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

358,148

376,934

Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

381,688

128,450

Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Private issue collateralized mortgage obligations [Member]

Financial Assets:

Securities available-for-sale

8,174

10,641

Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

30,107

Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Equity securities [Member]

Financial Assets:

Securities available-for-sale

4,146

Company Determined Fair Value (Level 3) [Member]

Financial Assets:

Securities available-for-sale

Customer interest rate swap agreement

Financial Liabilities:

Interest rate swap agreements

Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]

Financial Assets:

Trading account assets

Customer interest rate swap agreement

Financial Liabilities:

Interest rate swap agreements

Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of states and political subdivisions [Member]

Financial Assets:

Securities available-for-sale

Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Private issue collateralized mortgage obligations [Member]

Financial Assets:

Securities available-for-sale

Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of U.S. government sponsored enterprises [Member]

Financial Assets:

Securities available-for-sale

Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Equity securities [Member]

Financial Assets:

Securities available-for-sale

- 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.

+ References+ Details

- Definition

Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

+ References+ Details

- Definition

Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

+ References+ Details

- 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 Trading Securities which consist of all investments in certain debt and equity securities that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) or for which an entity has elected the fair value option. Trading generally reflects active and frequent buying and selling, and trading securities are generally used with the objective of generating profits on short-term differences in price, but this category of investments may also include items which are not intended to be sold in the near term or for which the fair value option has been elected.

+ References+ Details