Securities (Summary of Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	$ 559,967	$ 373,376
Available for sale securities unrealized gains	8,819	7,203
Available for sale securities unrealized losses	(4,530)	(5,535)
Available for sale, at fair value	564,256	375,044
Held to maturity securities	16,848	20,023
Held to maturity securities unrealized gains	644	493
Held to maturity securities unrealized losses	0	0
Held to maturity securities fair value	17,492	20,516
Total available for sale and held to maturity securities amortized cost	576,815	393,399
Total available for sale and held to maturity securities unrealized gains	9,463	7,696
Total available for sale and held to maturity securities unrealized losses	(4,530)	(5,535)
Total available for sale and held to maturity securities fair value	581,748	395,560
Obligations of U.S. government-sponsored enterprises [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	75,500	77,330
Available for sale securities unrealized gains	49	73
Available for sale securities unrealized losses	(65)	(388)
Available for sale, at fair value	75,484	77,015
Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	434,430	228,908
Available for sale securities unrealized gains	8,564	6,398
Available for sale securities unrealized losses	(307)	(450)
Available for sale, at fair value	442,687	234,856
Held to maturity securities	16,848	20,023
Held to maturity securities unrealized gains	644	493
Held to maturity securities unrealized losses	0	0
Held to maturity securities fair value	17,492	20,516
Obligations of states and political subdivisions [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	18,239	35,353
Available for sale securities unrealized gains	157	727
Available for sale securities unrealized losses	0	0
Available for sale, at fair value	18,396	36,080
Individual name issuer trust preferred debt securities
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	29,842	29,815
Available for sale securities unrealized gains	0	0
Available for sale securities unrealized losses	(4,158)	(4,677)
Available for sale, at fair value	25,684	25,138
Corporate bonds [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	1,956	1,970
Available for sale securities unrealized gains	49	5
Available for sale securities unrealized losses	0	(20)
Available for sale, at fair value	$ 2,005	$ 1,955

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

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