Fair Value Measurements (Financial Assets Measured at Fair Value on Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	$ 644,668
Residential MBSs [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	67,105
Fair value measurements, recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	644,668	675,109
Fair value measurements, recurring [Member] \| Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| Significant Other Observable Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	644,668	675,109
Fair value measurements, recurring [Member] \| Significant Unobservable Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| U.S. Government agency securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	31,003	33,761
Fair value measurements, recurring [Member] \| U.S. Government agency securities [Member] \| Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| U.S. Government agency securities [Member] \| Significant Other Observable Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	31,003	33,761
Fair value measurements, recurring [Member] \| U.S. Government agency securities [Member] \| Significant Unobservable Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| Residential MBSs [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	67,105	57,210
Fair value measurements, recurring [Member] \| Residential MBSs [Member] \| Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| Residential MBSs [Member] \| Significant Other Observable Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	67,105	57,210
Fair value measurements, recurring [Member] \| Residential MBSs [Member] \| Significant Unobservable Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	520,829	556,867
Fair value measurements, recurring [Member] \| Collateralized Mortgage Obligations [Member] \| Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| Collateralized Mortgage Obligations [Member] \| Significant Other Observable Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	520,829	556,867
Fair value measurements, recurring [Member] \| Collateralized Mortgage Obligations [Member] \| Significant Unobservable Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	25,731	27,271
Fair value measurements, recurring [Member] \| Municipal Securities [Member] \| Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	0	0
Fair value measurements, recurring [Member] \| Municipal Securities [Member] \| Significant Other Observable Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	25,731	27,271
Fair value measurements, recurring [Member] \| Municipal Securities [Member] \| Significant Unobservable Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Securities available for sale	$ 0	$ 0

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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