Securities (Amortized Cost, Unrealized Gross Gains and Losses Recognized in Accumulated Other Comprehensive Income (Loss), and Fair Value of Securities Available-for-Sale) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 617,785	$ 571,058
Gross Unrealized Gains	14,333	16,739
Gross Unrealized Losses	(1,237)	(195)
Fair Value	630,881	587,602
U.S. Treasury and Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,263	23,570
Gross Unrealized Gains	31	40
Gross Unrealized Losses	(130)	(138)
Fair Value	23,164	23,472
Obligations of State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	71,408	71,352
Gross Unrealized Gains	4,744	5,145
Gross Unrealized Losses	(34)	(12)
Fair Value	76,118	76,485
Mortgage-backed Securities - Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	522,430	475,452
Gross Unrealized Gains	9,470	11,505
Gross Unrealized Losses	(1,073)	(45)
Fair Value	530,827	486,912
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	684	684
Gross Unrealized Gains	88	49
Gross Unrealized Losses	0	0
Fair Value	$ 772	$ 733

Securities (Amortized Cost, Unrealized Gross Gains and Losses Recognized in Accumulated Other Comprehensive Income (Loss), and Fair Value of Securities Available-for-Sale) (Details) (USD $)
In Thousands, unless otherwise specified

Mar. 31, 2013

Dec. 31, 2012

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

$ 617,785

$ 571,058

Gross Unrealized Gains

14,333

16,739

Gross Unrealized Losses

(1,237)

(195)

Fair Value

630,881

587,602

U.S. Treasury and Agency Securities [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

23,263

23,570

Gross Unrealized Gains

Gross Unrealized Losses

(130)

(138)

Fair Value

23,164

23,472

Obligations of State and Political Subdivisions [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

71,408

71,352

Gross Unrealized Gains

4,744

5,145

Gross Unrealized Losses

(34)

(12)

Fair Value

76,118

76,485

Mortgage-backed Securities - Residential [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

522,430

475,452

Gross Unrealized Gains

9,470

11,505

Gross Unrealized Losses

(1,073)

(45)

Fair Value

530,827

486,912

Equity Securities [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

684

Gross Unrealized Gains

Gross Unrealized Losses

Fair Value

$ 772

$ 733

- Definition

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

+ References

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15D

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15C

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15E

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 22

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details