Securities (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	$ 789,229	$ 756,186
Available-for-sale, Unrealized Gains	3,174	4,293
Available-for-sale, Unrealized Losses	(12,536)	(10,141)
AFS securities	779,867	750,338
Held-to-maturity Securities	94,609	84,144
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	618	1,564
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(631)	(61)
Held-to-maturity Securities, Fair Value	94,596	85,647
US Government Corporations and Agencies Securities [Member]
Schedule of Investments [Line Items]
Held-to-maturity Securities	94,609	84,144
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	618	1,564
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(631)	(61)
Held-to-maturity Securities, Fair Value	94,596	85,647
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost		4,971
Available-for-sale, Unrealized Gains		69
Available-for-sale, Unrealized Losses		0
AFS securities		5,040
Obligations of states and political subdivisions [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	8,848	17,355
Available-for-sale, Unrealized Gains	153	339
Available-for-sale, Unrealized Losses	0	0
AFS securities	9,001	17,694
Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	485,222	419,429
Available-for-sale, Unrealized Gains	2,515	3,474
Available-for-sale, Unrealized Losses	(7,115)	(3,857)
AFS securities	480,622	419,046
Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	289,046	312,719
Available-for-sale, Unrealized Gains	265	409
Available-for-sale, Unrealized Losses	(5,421)	(6,271)
AFS securities	283,890	306,857
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	5,481	1,000
Available-for-sale, Unrealized Gains	132
Available-for-sale, Unrealized Losses	0	(4)
AFS securities	5,613	996
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	788,597	755,474
Available-for-sale, Unrealized Gains	3,065	4,291
Available-for-sale, Unrealized Losses	(12,536)	(10,132)
AFS securities	779,126	749,633
Equity Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	632	712
Available-for-sale, Unrealized Gains	109	2
Available-for-sale, Unrealized Losses	0	(9)
AFS securities	$ 741	$ 705

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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