Investment Securities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 558,818	$ 430,836
Gross Unrealized Gains	7,451	2,843
Gross Unrealized Losses	1,419	2,373
Estimated Fair Value	564,850	431,306
Obligations of U.S. Treasury and government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	6,646	7,081
Gross Unrealized Gains	335	107
Gross Unrealized Losses	0	0
Obligations of U.S. government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	22,118	32,479
Gross Unrealized Gains	55	36
Gross Unrealized Losses	0	151
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	5,918	6,075
Gross Unrealized Gains	120	16
Gross Unrealized Losses	0	1
Residential mortgage-backed securities - GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	436,344	348,884
Gross Unrealized Gains	5,678	2,611
Gross Unrealized Losses	948	1,222
Residential mortgage-backed securities - Private [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	22,649	33,111
Gross Unrealized Gains	750	73
Gross Unrealized Losses	454	967
Commercial mortgage-backed securities - GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	23,150
Gross Unrealized Gains	209
Gross Unrealized Losses	0
Estimated Fair Value	23,359
Commercial mortgage-backed securities - Private [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	5,283
Gross Unrealized Gains	34
Gross Unrealized Losses	0
Corporate notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	36,710	3,206
Gross Unrealized Gains	270	0
Gross Unrealized Losses	17	32
Segment, Continuing Operations [Member] \| Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	564,850	431,306
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	564,850	431,306
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member] \| Obligations of U.S. Treasury and government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	6,981	7,188
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member] \| Obligations of U.S. government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	22,173	32,364
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member] \| Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	6,038	6,090
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member] \| Residential mortgage-backed securities - GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	441,074	350,273
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member] \| Residential mortgage-backed securities - Private [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	22,945	32,217
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member] \| Commercial mortgage-backed securities - Private [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	5,317
Segment, Continuing Operations [Member] \| Level 2 [Member] \| Recurring [Member] \| Corporate notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 36,963	$ 3,174

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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