Investment Securities (Summary of Amortized Cost and Fair Value of Available-for-Sale Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	$ 749,187	$ 688,385
Investment securities available-for-sale, Unrealized Gains	3,003	3,587
Investment securities available-for-sale, Unrealized Losses	3,326	7,402
Available-for-sale, at fair value	748,864us-gaap_AvailableForSaleSecurities	684,570us-gaap_AvailableForSaleSecurities
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	8,272
Investment securities available-for-sale, Unrealized Gains	0
Investment securities available-for-sale, Unrealized Losses	13
Available-for-sale, at fair value	8,259
Government sponsored agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	263,658	93,895
Investment securities available-for-sale, Unrealized Gains	356	250
Investment securities available-for-sale, Unrealized Losses	511	382
Available-for-sale, at fair value	263,503	93,763
State and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	45,157	42,450
Investment securities available-for-sale, Unrealized Gains	1,087	1,355
Investment securities available-for-sale, Unrealized Losses	17	7
Available-for-sale, at fair value	46,227	43,798
Residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	240,465	303,495
Investment securities available-for-sale, Unrealized Gains	885	968
Investment securities available-for-sale, Unrealized Losses	1,543	5,097
Available-for-sale, at fair value	239,807	299,366
Collateralized mortgage obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	145,316	182,128
Investment securities available-for-sale, Unrealized Gains	261	452
Investment securities available-for-sale, Unrealized Losses	1,194	1,639
Available-for-sale, at fair value	144,383	180,941
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	44,930	65,028
Investment securities available-for-sale, Unrealized Gains	213	499
Investment securities available-for-sale, Unrealized Losses	48	252
Available-for-sale, at fair value	45,095	65,275
Preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available-for-sale, Amortized Cost	1,389	1,389
Investment securities available-for-sale, Unrealized Gains	201	63
Investment securities available-for-sale, Unrealized Losses	0	25
Available-for-sale, at fair value	$ 1,590	$ 1,427

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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