Investment Securities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	$ 719,556	$ 752,085
Gross Unrealized Gains	12,819	13,290
Gross Unrealized Losses	67,089	68,857
Available-for-sale securities estimated fair value	665,286	696,518
Cumulative OTTI in AOCI	48,771	49,401
U.S. Treasury securities and obligations of U.S. Government corporations and agencies [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	311,096	303,484
Gross Unrealized Gains	135	75
Gross Unrealized Losses	269	12
Available-for-sale securities estimated fair value	310,962	303,547
Cumulative OTTI in AOCI	0	0
State and political subdivisions [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	92,464	94,794
Gross Unrealized Gains	4,106	4,092
Gross Unrealized Losses	2	38
Available-for-sale securities estimated fair value	96,568	98,848
Cumulative OTTI in AOCI	0	0
Residential mortgage-backed securities, Agency [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	155,697	185,543
Gross Unrealized Gains	7,321	8,036
Gross Unrealized Losses	57	175
Available-for-sale securities estimated fair value	162,961	193,404
Cumulative OTTI in AOCI	0	0
Residential mortgage-backed securities, Non Agency [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	34,405	39,526
Gross Unrealized Gains	581	607
Gross Unrealized Losses	2,080	2,592
Available-for-sale securities estimated fair value	32,906	37,541
Cumulative OTTI in AOCI	2,080	2,234
Trust preferred collateralized debt obligations [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	101,388	104,161
Gross Unrealized Gains	0	0
Gross Unrealized Losses	60,604	61,792
Available-for-sale securities estimated fair value	40,784	42,369
Cumulative OTTI in AOCI	46,691	47,167
Single issue trust preferred securities [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	15,253	15,242
Gross Unrealized Gains	342	304
Gross Unrealized Losses	3,935	3,786
Available-for-sale securities estimated fair value	11,660	11,760
Cumulative OTTI in AOCI	0	0
Other corporate securities [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	4,995	4,994
Gross Unrealized Gains	157	96
Gross Unrealized Losses	0	0
Available-for-sale securities estimated fair value	5,152	5,090
Cumulative OTTI in AOCI	0	0
Marketable equity securities [Member]
Summary of amortized cost and fair values of available for sale securities
Amortized Cost	4,258	4,341
Gross Unrealized Gains	177	80
Gross Unrealized Losses	142	462
Available-for-sale securities estimated fair value	4,293	3,959
Cumulative OTTI in AOCI	$ 0	$ 0

Total of accumulated other comprehensive loss related to that portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized either as available-for-sale or held-to-maturity that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

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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.

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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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- 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.

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