Investments (Investments Classified by Contractual Maturity Date) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Amortized Cost And Estimated Fair Value Of Investment Securities Available For Sale By Contractual Maturity [Line Items]
Maturing within one year, Amortized Cost	$ 572	$ 686
Maturing after one year through five years, Amortized Cost	216,346	222,081
Maturing after five years through ten years, Amortized Cost	93,818	97,949
Maturing after ten years, Amortized Cost	51,612	54,531
Amortized Cost, Total	506,866	504,564
Maturing within one year, Fair Value	581	694
Maturing after one year through five years, Fair Value	219,788	225,415
Maturing after five years through ten years, Fair Value	95,802	99,583
Maturing after ten years, Fair Value	52,960	55,705
Fair Value, Total	514,466us-gaap_AvailableForSaleSecurities	511,883us-gaap_AvailableForSaleSecurities
U.S Government agencies collateralized by mortgage obligations [Member]
Amortized Cost And Estimated Fair Value Of Investment Securities Available For Sale By Contractual Maturity [Line Items]
Amortized Cost, Total	143,309	128,107
Fair Value, Total	143,064	128,264
Other securities [Member]
Amortized Cost And Estimated Fair Value Of Investment Securities Available For Sale By Contractual Maturity [Line Items]
Amortized Cost, Total	1,209	1,210
Fair Value, Total	$ 2,271	$ 2,222

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

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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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Amount after adjustments of available-for-sale debt securities at cost, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing after the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing after the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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