Securities (Amortized Cost, Unrealized Gross Gains and Losses Recognized in Accumulated Other Comprehensive Income (Loss), and Fair Value of Securities Available-for-Sale) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 575,582	$ 614,085
Gross Unrealized Gains	8,616	5,885
Gross Unrealized Losses	(8,457)	(13,938)
Fair Value	575,741	606,032
U.S. Treasury and Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,000	20,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(637)	(1,048)
Fair Value	19,363	18,952
Obligations of State and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	134,763	112,008
Gross Unrealized Gains	5,858	2,388
Gross Unrealized Losses	(92)	(899)
Fair Value	140,529	113,497
Mortgage-backed Securities - Residential
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	420,466	481,724
Gross Unrealized Gains	2,758	3,497
Gross Unrealized Losses	(7,728)	(11,991)
Fair Value	415,496	473,230
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	353	353
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 353	$ 353