Investment Securities (Available-for-sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 628,584	$ 617,128
Gross unrealized gains	21,260	23,058
Gross unrealized losses	(10,659)	(11,615)
Available-for-sale securities, total fair value	639,185	628,571
U.S. Treasury and government agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	26	32
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Available-for-sale securities, total fair value	26	32
U.S. government sponsored agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	486	12,291
Gross unrealized gains	30	746
Gross unrealized losses	0	0
Available-for-sale securities, total fair value	516	13,037
States and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	42,458	32,763
Gross unrealized gains	3,292	2,982
Gross unrealized losses	(82)	0
Available-for-sale securities, total fair value	45,668	35,745
Residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	511,305	521,231
Gross unrealized gains	12,558	15,607
Gross unrealized losses	(9,767)	(9,835)
Available-for-sale securities, total fair value	514,096	527,003
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	62,129	35,712
Gross unrealized gains	2,330	1,577
Gross unrealized losses	(43)	0
Available-for-sale securities, total fair value	64,416	37,289
Bank-issued trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	10,966	13,886
Gross unrealized gains	73	12
Gross unrealized losses	(682)	(1,687)
Available-for-sale securities, total fair value	10,357	12,211
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	1,214	1,213
Gross unrealized gains	2,977	2,134
Gross unrealized losses	(85)	(93)
Available-for-sale securities, total fair value	$ 4,106	$ 3,254

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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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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