Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Available for Sale, Amortized Cost
Available for sale Securities, Amortized Cost	$ 454,575	$ 448,219
Available for Sale, Fair Value
Available for sale Securities, Fair Value, Total	442,929	447,498
Held to Maturity, Amortized Cost
Held to maturity Securities, Amortized Cost	538,261	497,688
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Total	523,288	494,194
Debt Securities
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	1,519
Available for Sale, Amortized Cost, Due after one year to five years	64,261
Available for Sale, Amortized Cost, Due after five to ten years	108,829
Available for Sale, Amortized Cost, Due after ten years	279,966
Available for sale Securities, Amortized Cost	454,575
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	1,522
Available for Sale, Fair Value, Due after one year to five years	63,023
Available for Sale, Fair Value, Due after five to ten years	106,155
Available for Sale, Fair Value, Due after ten years	272,229
Available for sale Securities, Fair Value, Total	442,929
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	10,003
Held to Maturity, Amortized Cost, Due after five to ten years	32,590
Held to Maturity, Amortized Cost, Due after ten years	495,668
Held to maturity Securities, Amortized Cost	538,261
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	9,860
Held to Maturity, Fair Value, Due after five to ten years	32,078
Held to Maturity, Fair Value, Due after ten years	481,350
Held to Maturity, Fair Value, Total	523,288
U.S. Government agency securities
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	999
Available for Sale, Amortized Cost, Due after one year to five years	20,014
Available for Sale, Amortized Cost, Due after five to ten years	12,466
Available for Sale, Amortized Cost, Due after ten years	0
Available for sale Securities, Amortized Cost	33,479	35,475
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	998
Available for Sale, Fair Value, Due after one year to five years	19,781
Available for Sale, Fair Value, Due after five to ten years	11,940
Available for Sale, Fair Value, Due after ten years	0
Available for sale Securities, Fair Value, Total	32,719	35,430
Small Business Administration Pooled Securities [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	46,102
Available for sale Securities, Amortized Cost	46,102	47,852
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	44,998
Available for sale Securities, Fair Value, Total	44,998	47,778
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	0
Held to Maturity, Amortized Cost, Due after five to ten years	0
Held to Maturity, Amortized Cost, Due after ten years	25,711
Held to maturity Securities, Amortized Cost	25,711	27,416
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	0
Held to Maturity, Fair Value, Due after five to ten years	0
Held to Maturity, Fair Value, Due after ten years	25,409
Held to Maturity, Fair Value, Total	25,409	27,399
Pooled trust preferred securities issued by banks and insurers
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	2,166
Available for sale Securities, Amortized Cost	2,166	2,179
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	1,751
Available for sale Securities, Fair Value, Total	1,751	1,640
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	1,320
Available for sale Securities, Amortized Cost	1,320	2,012
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	1,329
Available for sale Securities, Fair Value, Total	1,329	2,016
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	0
Held to Maturity, Amortized Cost, Due after five to ten years	1,500
Held to Maturity, Amortized Cost, Due after ten years	0
Held to maturity Securities, Amortized Cost	1,500	1,500
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	0
Held to Maturity, Fair Value, Due after five to ten years	1,523
Held to Maturity, Fair Value, Due after ten years	0
Held to Maturity, Fair Value, Total	1,523	1,529
US States and Political Subdivisions Debt Securities [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	1,024
Available for Sale, Amortized Cost, Due after five to ten years	953
Available for Sale, Amortized Cost, Due after ten years	0
Available for sale Securities, Amortized Cost	1,977	2,237
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	1,026
Available for Sale, Fair Value, Due after five to ten years	970
Available for Sale, Fair Value, Due after ten years	0
Available for sale Securities, Fair Value, Total	1,996	2,274
Collateralized Debt Obligations [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	150,122
Available for sale Securities, Amortized Cost	150,122	124,098
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	145,147
Available for sale Securities, Fair Value, Total	145,147	122,012
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	0
Held to Maturity, Amortized Cost, Due after five to ten years	1,179
Held to Maturity, Amortized Cost, Due after ten years	322,567
Held to maturity Securities, Amortized Cost	323,746	262,998
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	0
Held to Maturity, Fair Value, Due after five to ten years	1,175
Held to Maturity, Fair Value, Due after ten years	312,167
Held to Maturity, Fair Value, Total	313,342	258,408
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	520
Available for Sale, Amortized Cost, Due after one year to five years	43,223
Available for Sale, Amortized Cost, Due after five to ten years	95,410
Available for Sale, Amortized Cost, Due after ten years	80,256
Available for sale Securities, Amortized Cost	219,409	214,934
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	524
Available for Sale, Fair Value, Due after one year to five years	42,216
Available for Sale, Fair Value, Due after five to ten years	93,245
Available for Sale, Fair Value, Due after ten years	79,004
Available for sale Securities, Fair Value, Total	214,989	215,764
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	8,998
Held to Maturity, Amortized Cost, Due after five to ten years	29,911
Held to Maturity, Amortized Cost, Due after ten years	147,390
Held to maturity Securities, Amortized Cost	186,299	204,768
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	8,846
Held to Maturity, Fair Value, Due after five to ten years	29,380
Held to Maturity, Fair Value, Due after ten years	143,774
Held to Maturity, Fair Value, Total	182,000	205,823
US Treasury Securities [Member]
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	1,005
Held to Maturity, Amortized Cost, Due after five to ten years	0
Held to Maturity, Amortized Cost, Due after ten years	0
Held to maturity Securities, Amortized Cost	1,005	1,006
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	1,014
Held to Maturity, Fair Value, Due after five to ten years	0
Held to Maturity, Fair Value, Due after ten years	0
Held to Maturity, Fair Value, Total	$ 1,014	$ 1,035