Investment Securities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 473,438	$ 430,836
Gross unrealized gains	4,896	2,843
Gross unrealized losses	1,198	2,373
Estimated fair value	477,136	431,306
Obligations of U.S. Treasury and government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	6,864	7,081
Gross unrealized gains	232	107
Gross unrealized losses	0	0
Estimated fair value	7,096	7,188
Obligations of U.S. government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	3,586	32,479
Gross unrealized gains	30	36
Gross unrealized losses	0	151
Estimated fair value	3,616	32,364
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	5,988	6,075
Gross unrealized gains	78	16
Gross unrealized losses	0	1
Estimated fair value	6,066	6,090
Residential mortgage-backed securities - GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	381,857	348,884
Gross unrealized gains	3,904	2,611
Gross unrealized losses	259	1,222
Estimated fair value	385,502	350,273
Residential mortgage-backed securities - private [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	32,797	33,111
Gross unrealized gains	652	73
Gross unrealized losses	769	967
Estimated fair value	32,680	32,217
Commercial mortgage-backed securities - private [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	5,354
Gross unrealized gains	0
Gross unrealized losses	15
Estimated fair value	5,339
Corporate notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	36,992	3,206
Gross unrealized gains	0	0
Gross unrealized losses	155	32
Estimated fair value	$ 36,837	$ 3,174

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

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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

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

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

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

-Publisher FASB

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-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

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-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

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+ 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