Securities (Reconciliation of fair value of securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	$ 426,340	$ 363,366
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	5,128	3,890
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(2,343)	(3,612)
Available-for-sale Securities	429,125	363,644
Held to maturity Securities, Amortized Cost	478,798	487,076
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	4,061	3,556
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(3,197)	(4,982)
Held to Maturity, Fair Value, Total	479,662	485,650
Amortized Cost	905,138	850,442
Gross Unrealized Gains	9,189	7,446
Unrealized Losses Other	(5,540)	(8,594)
Fair Value	908,787	849,294
U. S. Government Agency Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	23,010	24,006
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	218	238
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	23,228	24,244
U.S. Treasury securities
Reconciliation of fair value of securities
Held to maturity Securities, Amortized Cost	1,006	1,007
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	42	47
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held to Maturity, Fair Value, Total	1,048	1,054
Agency mortgage-backed securities
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	211,757	173,268
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	3,060	2,852
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(253)	(736)
Available-for-sale Securities	214,564	175,384
Held to maturity Securities, Amortized Cost	171,664	156,088
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	2,508	2,274
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(192)	(858)
Held to Maturity, Fair Value, Total	173,980	157,504
Agency Collateralized Mortgage Obligations [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	115,504	101,094
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	405	106
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(1,080)	(1,332)
Available-for-sale Securities	114,829	99,868
Held to maturity Securities, Amortized Cost	275,894	297,445
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,244	1,002
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(2,905)	(3,797)
Held to Maturity, Fair Value, Total	274,233	294,650
State, County, and Municipal Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	2,492	3,743
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	47	50
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	2,539	3,793
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	2,025	2,311
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	19	3
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	(3)
Available-for-sale Securities	2,044	2,311
Held to maturity Securities, Amortized Cost	1,500	1,500
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	39	44
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held to Maturity, Fair Value, Total	1,539	1,544
Pooled trust preferred securities issued by banks and insurers
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	2,182	2,200
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(558)	(616)
Available-for-sale Securities	1,624	1,584
Small Business Administration Pooled Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	50,194	37,561
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	45	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(53)	(372)
Available-for-sale Securities	50,186	37,189
Held to maturity Securities, Amortized Cost	28,734	31,036
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	228	189
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(100)	(327)
Held to Maturity, Fair Value, Total	28,862	30,898
Equity securities
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	19,176	19,183
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,334	641
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(399)	(553)
Available-for-sale Securities	$ 20,111	$ 19,271

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Available for sale securities and held to maturity securities gross unrealized gains.

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

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

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