Securities (Schedule of Securities Available-for-Sale) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 617,996	$ 626,383
Gross Unrealized Gains	6,986	10,130
Gross Unrealized Losses	(6,186)	(5,518)
Securities Available-for-Sale, at Fair Value	618,796	630,995
U.S. Treasury and Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,000	20,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(110)	(439)
Securities Available-for-Sale, at Fair Value	9,890	19,561
Obligations of State and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	178,386	147,321
Gross Unrealized Gains	4,812	6,515
Gross Unrealized Losses	(1,110)	(59)
Securities Available-for-Sale, at Fair Value	182,088	153,777
Mortgage-backed Securities - Residential
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	429,257	458,709
Gross Unrealized Gains	2,174	3,615
Gross Unrealized Losses	(4,966)	(5,020)
Securities Available-for-Sale, at Fair Value	426,465	457,304
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	353	353
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Securities Available-for-Sale, at Fair Value	$ 353	$ 353