Investment Securities (Unrealized Gains) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	$ 417,470	$ 482,440
Investment Securities Available-for-Sale: Unrealized Gains	8,036	16,316
Investment Securities Available-for-Sale: Unrealized Losses	(5,733)	(1,941)
Investment securities: Available-for-sale	419,773	496,815
Investment Securities Held-to-Maturity: Amortized Cost	136,786	58,064
Investment Securities Held-to-Maturity: Unrealized Gains	2,113	4,372
Investment Securities Held-to-Maturity: Unrealized Losses	(3,545)	(5)
Investment Securities Held-to-Maturity: Fair Value	135,354	62,431
Total investment securities, amortized cost	554,256	540,504
Total investment securities, gross unrealized gains	10,149	20,688
Total investment securities, gross unrealized losses	(9,278)	(1,946)
Total investment securities, fair value	555,127	559,246
U.S. treasury notes [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	43,450	11,870
Investment Securities Available-for-Sale: Unrealized Gains	0	62
Investment Securities Available-for-Sale: Unrealized Losses	(1,312)	(23)
Investment securities: Available-for-sale	42,138	11,909
Federal agency obligations [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	14,265	20,207
Investment Securities Available-for-Sale: Unrealized Gains	30	333
Investment Securities Available-for-Sale: Unrealized Losses	(437)	(5)
Investment securities: Available-for-sale	13,858	20,535
Investment Securities Held-to-Maturity: Amortized Cost	3,698	4,178
Investment Securities Held-to-Maturity: Unrealized Gains	68	79
Investment Securities Held-to-Maturity: Unrealized Losses	0	0
Investment Securities Held-to-Maturity: Fair Value	3,766	4,257
Residential mortgage-backed securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	48,925	52,400
Investment Securities Available-for-Sale: Unrealized Gains	682	1,385
Investment Securities Available-for-Sale: Unrealized Losses	(221)	(1)
Investment securities: Available-for-sale	49,386	53,784
Commercial mortgage-backed securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	9,709	9,725
Investment Securities Available-for-Sale: Unrealized Gains	0	244
Investment Securities Available-for-Sale: Unrealized Losses	(288)	0
Investment securities: Available-for-sale	9,421	9,969
Investment Securities Held-to-Maturity: Amortized Cost	4,965	5,501
Investment Securities Held-to-Maturity: Unrealized Gains	0	154
Investment Securities Held-to-Maturity: Unrealized Losses	(98)	(5)
Investment Securities Held-to-Maturity: Fair Value	4,867	5,650
Obligations of U.S. states and political subdivisions [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	39,341	103,193
Investment Securities Available-for-Sale: Unrealized Gains	1,092	4,653
Investment Securities Available-for-Sale: Unrealized Losses	(25)	(132)
Investment securities: Available-for-sale	40,408	107,714
Investment Securities Held-to-Maturity: Amortized Cost	118,032	48,385
Investment Securities Held-to-Maturity: Unrealized Gains	2,045	4,139
Investment Securities Held-to-Maturity: Unrealized Losses	(3,365)	0
Investment Securities Held-to-Maturity: Fair Value	116,712	52,524
Trust preferred securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	20,620	22,279
Investment Securities Available-for-Sale: Unrealized Gains	224	144
Investment Securities Available-for-Sale: Unrealized Losses	(1,157)	(1,174)
Investment securities: Available-for-sale	19,687	21,249
Investment Securities Held-to-Maturity: Amortized Cost	10,091
Investment Securities Held-to-Maturity: Unrealized Gains	0
Investment Securities Held-to-Maturity: Unrealized Losses	(82)
Investment Securities Held-to-Maturity: Fair Value	10,009
Corporate bonds and notes [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	215,263	228,681
Investment Securities Available-for-Sale: Unrealized Gains	5,667	9,095
Investment Securities Available-for-Sale: Unrealized Losses	(2,128)	(371)
Investment securities: Available-for-sale	218,802	237,405
Collateralized mortgage obligations [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost		2,120
Investment Securities Available-for-Sale: Unrealized Gains	24	0
Investment Securities Available-for-Sale: Unrealized Losses		0
Investment securities: Available-for-sale		2,120
Asset-backed securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	19,038	19,431
Investment Securities Available-for-Sale: Unrealized Gains	243	311
Investment Securities Available-for-Sale: Unrealized Losses	0	0
Investment securities: Available-for-sale	19,281	19,742
Certificates of Deposit [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	2,402	2,854
Investment Securities Available-for-Sale: Unrealized Gains	30	21
Investment Securities Available-for-Sale: Unrealized Losses	(29)	(10)
Investment securities: Available-for-sale	2,403	2,865
Equity securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	376	535
Investment Securities Available-for-Sale: Unrealized Gains	0	0
Investment Securities Available-for-Sale: Unrealized Losses	(121)	(210)
Investment securities: Available-for-sale	255	325
Other securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	4,081	9,145
Investment Securities Available-for-Sale: Unrealized Gains	68	68
Investment Securities Available-for-Sale: Unrealized Losses	(15)	(15)
Investment securities: Available-for-sale	$ 4,134	$ 9,198