Investment Securities (Available-for-sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities
Amortized Cost	$ 598,445	$ 621,126
Gross Unrealized Gains	10,645	10,520
Gross Unrealized Losses	(16,993)	(25,538)
Fair Value	592,097	606,108
U.S. Treasury and government agencies
Schedule of Available-for-sale Securities
Amortized Cost	19	20
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	19	20
U.S. government sponsored agencies
Schedule of Available-for-sale Securities
Amortized Cost	287	308
Gross Unrealized Gains	8	11
Gross Unrealized Losses	0	0
Fair Value	295	319
States and political subdivisions
Schedule of Available-for-sale Securities
Amortized Cost	50,365	50,509
Gross Unrealized Gains	1,814	1,480
Gross Unrealized Losses	(511)	(1,027)
Fair Value	51,668	50,962
Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Amortized Cost	510,072	527,283
Gross Unrealized Gains	5,186	5,334
Gross Unrealized Losses	(14,742)	(22,520)
Fair Value	500,516	510,097
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities
Amortized Cost	27,885	33,256
Gross Unrealized Gains	0	274
Gross Unrealized Losses	(1,135)	(1,226)
Fair Value	26,750	32,304
Bank-issued trust preferred securities
Schedule of Available-for-sale Securities
Amortized Cost	8,513	8,508
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(520)	(679)
Fair Value	7,995	7,829
Equity securities
Schedule of Available-for-sale Securities
Amortized Cost	1,304	1,242
Gross Unrealized Gains	3,635	3,421
Gross Unrealized Losses	(85)	(86)
Fair Value	$ 4,854	$ 4,577