Securities (Reconciliation of fair value of securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	$ 454,575	$ 448,219
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,137	3,740
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(12,783)	(4,461)
Available-for-sale Securities	442,929	447,498
Held to maturity Securities, Amortized Cost	538,261	497,688
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	520	2,429
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(15,493)	(5,923)
Held to Maturity, Fair Value, Total	523,288	494,194
Amortized Cost	992,836	945,907
Gross Unrealized Gains	1,657	6,169
Unrealized Losses Other	(28,276)	(10,384)
Fair Value	966,217	941,692
U. S. Government Agency Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	33,479	35,475
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		86
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(760)	(131)
Available-for-sale Securities	32,719	35,430
U.S. Treasury securities
Reconciliation of fair value of securities
Held to maturity Securities, Amortized Cost	1,005	1,006
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	9	29
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held to Maturity, Fair Value, Total	1,014	1,035
Agency mortgage-backed securities
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	219,409	214,934
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,019	1,897
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(5,439)	(1,067)
Available-for-sale Securities	214,989	215,764
Held to maturity Securities, Amortized Cost	186,299	204,768
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	286	1,791
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(4,585)	(736)
Held to Maturity, Fair Value, Total	182,000	205,823
Agency Collateralized Mortgage Obligations [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	150,122	124,098
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	90	78
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(5,065)	(2,164)
Available-for-sale Securities	145,147	122,012
Held to maturity Securities, Amortized Cost	323,746	262,998
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	151	397
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(10,555)	(4,987)
Held to Maturity, Fair Value, Total	313,342	258,408
State, County, and Municipal Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	1,977	2,237
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	19	37
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	1,996	2,274
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	1,320	2,012
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	9	4
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	1,329	2,016
Held to maturity Securities, Amortized Cost	1,500	1,500
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	23	29
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held to Maturity, Fair Value, Total	1,523	1,529
Pooled trust preferred securities issued by banks and insurers
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	2,166	2,179
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(415)	(539)
Available-for-sale Securities	1,751	1,640
Small Business Administration Pooled Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	46,102	47,852
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	44
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(1,104)	(118)
Available-for-sale Securities	44,998	47,778
Held to maturity Securities, Amortized Cost	25,711	27,416
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	51	183
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(353)	(200)
Held to Maturity, Fair Value, Total	25,409	27,399
Equity securities
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	0	19,432
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		1,594
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 0	(442)
Available-for-sale Securities		$ 20,584

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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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