Securities (Schedule of Securities Available-for-Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 729,942	$ 719,555
Gross Unrealized Gains	6,264	4,327
Gross Unrealized Losses	(9,854)	(14,096)
Total Fair Value	726,352	709,786
Obligations of State and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	254,587	247,350
Gross Unrealized Gains	5,169	3,847
Gross Unrealized Losses	(2,413)	(3,678)
Total Fair Value	257,343	247,519
MBS/CMO - Residential
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	475,002	471,852
Gross Unrealized Gains	1,095	480
Gross Unrealized Losses	(7,441)	(10,418)
Total Fair Value	468,656	461,914
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	353	353
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total Fair Value	$ 353	$ 353