Investments - Carrying value and estimated fair value (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities
Equity Securities, Amortized Cost	$ 7,596	$ 7,596
Available-for-sale investment securities, Amortized cost	312,175	321,405
Gross Unrealized Gains	12,410	9,674
Gross Unrealized Losses	(1,654)	(2,666)
Equity Securities, Estimated Fair Value	7,976	7,891
Available-for-sale Securities	322,931	328,413
U.S. Government agencies
Schedule of Available-for-sale Securities
Debt Securities, Amortized Cost		149
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Debt Securities, Estimated Fair Value		149
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities
Debt Securities, Amortized Cost	106,675	101,030
Gross Unrealized Gains	9,411	7,732
Gross Unrealized Losses	(272)	(331)
Debt Securities, Estimated Fair Value	115,814	108,431
U.S. Government agencies collateralized by residential mortgage obligations
Schedule of Available-for-sale Securities
Debt Securities, Amortized Cost	190,654	204,222
Gross Unrealized Gains	2,410	1,402
Gross Unrealized Losses	(592)	(1,080)
Debt Securities, Estimated Fair Value	192,472	204,544
Private label residential mortgage backed securities
Schedule of Available-for-sale Securities
Debt Securities, Amortized Cost	7,250	8,408
Gross Unrealized Gains	209	245
Gross Unrealized Losses	(790)	(1,255)
Debt Securities, Estimated Fair Value	6,669	7,398
Other equity securities
Schedule of Available-for-sale Securities
Gross Unrealized Gains	380	295
Gross Unrealized Losses	$ 0	$ 0

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

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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

Amount of debt securities categorized neither as held-to-maturity nor trading.

+ References

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+ Details

- Definition

Amount of equity securities categorized neither as held-to-maturity nor as trading.

+ References

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+ 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