Securities (Schedule of Securities with Unrealized Losses) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	$ 327,716	$ 464,958
Less than 12 Months Unrealized Loss	(4,002)	(12,460)
12 Months or More Fair Value	54,100	47,271
12 Months or More Unrealized Loss	(1,491)	(1,636)
Total Fair Value	381,816	512,229
Total Unrealized Loss	(5,493)	(14,096)
Obligations of State and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	33,584	108,918
Less than 12 Months Unrealized Loss	(337)	(3,678)
12 Months or More Fair Value	6,115	0
12 Months or More Unrealized Loss	(233)	0
Total Fair Value	39,699	108,918
Total Unrealized Loss	(570)	(3,678)
MBS/CMO - Residential
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	294,132	356,040
Less than 12 Months Unrealized Loss	(3,665)	(8,782)
12 Months or More Fair Value	47,985	47,271
12 Months or More Unrealized Loss	(1,258)	(1,636)
Total Fair Value	342,117	403,311
Total Unrealized Loss	(4,923)	(10,418)
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	0	0
Less than 12 Months Unrealized Loss	0	0
12 Months or More Fair Value	0	0
12 Months or More Unrealized Loss	0	0
Total Fair Value	0	0
Total Unrealized Loss	$ 0	$ 0