Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Available for Sale, Fair Value
Debt Securities, Available-for-sale, Amortized Cost	$ 383,610	$ 450,548
Debt Securities, Available-for-sale	391,975	442,752
Held to Maturity, Amortized Cost
Held to maturity Securities, Amortized Cost	777,270	611,490
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Total	792,163	603,640
Available for Sale Securities and Held to Maturity Securities Amortized Cost	1,160,880	1,062,038
Debt Securities, Available-for-sale and Held-to-maturity	1,184,138	1,046,392
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	10,002
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	10,003
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	107,439
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	108,644
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	107,758
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	110,909
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Amortized Cost	935,681
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Fair Value	954,582
U.S. Government agency securities
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available for Sale, Amortized Cost, Due in one year or less	10,002
Available for Sale, Amortized Cost, Due after one year to five years	10,003
Available for Sale, Amortized Cost, Due after five to ten years	12,470
Available for Sale, Amortized Cost, Due after ten years	0
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	10,003
Available for Sale, Fair Value, Due after one year to five years	10,154
Available for Sale, Fair Value, Due after five to ten years	13,145
Available for Sale, Fair Value, Due after ten years	0
Debt Securities, Available-for-sale, Amortized Cost	32,475	32,477
Debt Securities, Available-for-sale	33,302	32,038
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	12,853
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	12,853	0
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	12,999
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	12,999
Small Business Administration Pooled Securities [Member]
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
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	58,360
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	59,970
Debt Securities, Available-for-sale, Amortized Cost	58,360	53,317
Debt Securities, Available-for-sale	59,970	51,927
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	33,212
Held to maturity Securities, Amortized Cost	33,212	23,727
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	33,919
Held to Maturity, Fair Value, Total	33,919	23,483
Debt Securities [Member]
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available for Sale, Amortized Cost, Due in one year or less	10,002
Available for Sale, Amortized Cost, Due after one year to five years	82,301
Available for Sale, Amortized Cost, Due after five to ten years	69,246
Available for Sale, Amortized Cost, Due after ten years	222,061
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	10,003
Available for Sale, Fair Value, Due after one year to five years	83,316
Available for Sale, Fair Value, Due after five to ten years	71,896
Available for Sale, Fair Value, Due after ten years	226,760
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	25,138
Held to Maturity, Amortized Cost, Due after five to ten years	38,512
Held to Maturity, Amortized Cost, Due after ten years	713,620
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	25,328
Held to Maturity, Fair Value, Due after five to ten years	39,013
Held to Maturity, Fair Value, Due after ten years	727,822
Held to Maturity, Fair Value, Total	792,163
Pooled trust preferred securities issued by banks and insurers
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
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	1,493
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	1,106
Debt Securities, Available-for-sale, Amortized Cost	1,493	1,678
Debt Securities, Available-for-sale	1,106	1,329
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
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	717
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	720
Debt Securities, Available-for-sale, Amortized Cost	717	717
Debt Securities, Available-for-sale	720	707
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	1,490
Held to Maturity, Fair Value, Due after ten years	0
Held to Maturity, Fair Value, Total	1,490	1,490
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	1,021
Available for Sale, Amortized Cost, Due after five to ten years	692
Available for Sale, Amortized Cost, Due after ten years	0
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	1,024
Available for Sale, Fair Value, Due after five to ten years	712
Available for Sale, Fair Value, Due after ten years	0
Debt Securities, Available-for-sale, Amortized Cost	1,713	1,719
Debt Securities, Available-for-sale	1,736	1,735
Agency Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
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	92,574
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	94,538
Debt Securities, Available-for-sale, Amortized Cost	92,574	138,149
Debt Securities, Available-for-sale	94,538	134,911
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	154
Held to Maturity, Amortized Cost, Due after five to ten years	0
Held to Maturity, Amortized Cost, Due after ten years	310,198
Held to maturity Securities, Amortized Cost	310,352	332,775
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	154
Held to Maturity, Fair Value, Due after five to ten years	0
Held to Maturity, Fair Value, Due after ten years	315,368
Held to Maturity, Fair Value, Total	315,522	326,724
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	71,277
Available for Sale, Amortized Cost, Due after five to ten years	56,084
Available for Sale, Amortized Cost, Due after ten years	68,917
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	72,138
Available for Sale, Fair Value, Due after five to ten years	58,039
Available for Sale, Fair Value, Due after ten years	70,426
Debt Securities, Available-for-sale, Amortized Cost	196,278	222,491
Debt Securities, Available-for-sale	200,603	220,105
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	11,128
Held to Maturity, Amortized Cost, Due after five to ten years	37,012
Held to Maturity, Amortized Cost, Due after ten years	370,210
Held to maturity Securities, Amortized Cost	418,350	252,484
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	11,153
Held to Maturity, Fair Value, Due after five to ten years	37,523
Held to Maturity, Fair Value, Due after ten years	378,535
Held to Maturity, Fair Value, Total	427,211	250,928
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	1,003
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	1,003	1,004
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	1,022
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	$ 1,022	$ 1,015