Securities (Schedule of Securities with Unrealized Losses) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	$ 411,695	$ 464,958
Less than 12 Months Unrealized Loss	(8,405)	(12,460)
12 Months or More Fair Value	45,218	47,271
12 Months or More Unrealized Loss	(1,449)	(1,636)
Total Fair Value	456,913	512,229
Total Unrealized Loss	(9,854)	(14,096)
Obligations of State and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	79,834	108,918
Less than 12 Months Unrealized Loss	(2,413)	(3,678)
12 Months or More Fair Value	0	0
12 Months or More Unrealized Loss	0	0
Total Fair Value	79,834	108,918
Total Unrealized Loss	(2,413)	(3,678)
MBS/CMO - Residential
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	331,861	356,040
Less than 12 Months Unrealized Loss	(5,992)	(8,782)
12 Months or More Fair Value	45,218	47,271
12 Months or More Unrealized Loss	(1,449)	(1,636)
Total Fair Value	377,079	403,311
Total Unrealized Loss	(7,441)	(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