Securities (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	$ 756,186	$ 763,553
Available-for-sale, Unrealized Gains	4,293	7,434
Available-for-sale, Unrealized Losses	(10,141)	(7,924)
AFS securities	750,338	763,063
Held-to-maturity Securities	84,144	20,179
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,564	265
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(61)	(19)
Held-to-maturity Securities, Fair Value	85,647	20,425
US Government Corporations and Agencies Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	4,971	4,962
Available-for-sale, Unrealized Gains	69	65
Available-for-sale, Unrealized Losses	0	0
AFS securities	5,040	5,027
Held-to-maturity Securities	84,144	20,179
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,564	265
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(61)	(19)
Held-to-maturity Securities, Fair Value	85,647	20,425
Obligations of states and political subdivisions [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	17,355	26,080
Available-for-sale, Unrealized Gains	339	697
Available-for-sale, Unrealized Losses	0	0
AFS securities	17,694	26,777
Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	419,429	377,657
Available-for-sale, Unrealized Gains	3,474	5,656
Available-for-sale, Unrealized Losses	(3,857)	(2,005)
AFS securities	419,046	381,308
Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	312,719	348,855
Available-for-sale, Unrealized Gains	409	953
Available-for-sale, Unrealized Losses	(6,271)	(5,911)
AFS securities	306,857	343,897
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	1,000
Available-for-sale, Unrealized Losses	(4)
AFS securities	996
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	755,474
Available-for-sale, Unrealized Gains	4,291
Available-for-sale, Unrealized Losses	(10,132)
AFS securities	749,633
Equity Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	712
Available-for-sale, Unrealized Gains	2
Available-for-sale, Unrealized Losses	(9)
AFS securities	$ 705
Private issue collateralized mortgage obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost		5,999
Available-for-sale, Unrealized Gains		63
Available-for-sale, Unrealized Losses		(8)
AFS securities		$ 6,054

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

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

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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