Investment Securities (Unrealized Gains) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	$ 495,859	$ 417,939
Investment Securities Available-for-Sale: Unrealized Gains	16,654	6,714
Investment Securities Available-for-Sale: Unrealized Losses	(2,908)	(10,146)
Investment Securities Available-for-Sale: Fair Value	509,605	414,507
Investment Securities Held-to-Maturity: Amortized Cost	56,503	72,233
Investment Securities Held-to-Maturity: Unrealized Gains	4,452	2,792
Investment Securities Held-to-Maturity: Unrealized Losses	(9)	(103)
Investment Securities Held-to-Maturity: Fair Value	60,946	74,922
Total investment securities, amortized cost	552,362	490,172
Total investment securities, gross unrealized gains	21,106	9,506
Total investment securities, gross unrealized losses	(2,917)	(10,249)
Total investment securities, fair value	570,551	489,429
U.S. treasury notes [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	20,571
Investment Securities Available-for-Sale: Unrealized Gains	111
Investment Securities Available-for-Sale: Unrealized Losses	(50)
Investment Securities Available-for-Sale: Fair Value	20,632
Federal agency obligations [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	27,928	24,781
Investment Securities Available-for-Sale: Unrealized Gains	514	188
Investment Securities Available-for-Sale: Unrealized Losses	(4)
Investment Securities Available-for-Sale: Fair Value	28,438	24,969
Investment Securities Held-to-Maturity: Amortized Cost	11,663	28,262
Investment Securities Held-to-Maturity: Unrealized Gains	80	177
Investment Securities Held-to-Maturity: Unrealized Losses		(34)
Investment Securities Held-to-Maturity: Fair Value	11,743	28,405
Residential mortgage-backed securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	57,695	113,213
Investment Securities Available-for-Sale: Unrealized Gains	1,804	2,157
Investment Securities Available-for-Sale: Unrealized Losses		(6)
Investment Securities Available-for-Sale: Fair Value	59,499	115,364
Commercial mortgage-backed securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	9,734
Investment Securities Available-for-Sale: Unrealized Gains	267
Investment Securities Available-for-Sale: Fair Value	10,001
Investment Securities Held-to-Maturity: Amortized Cost	5,598	6,276
Investment Securities Held-to-Maturity: Unrealized Gains	179
Investment Securities Held-to-Maturity: Unrealized Losses	(9)	(69)
Investment Securities Held-to-Maturity: Fair Value	5,768	6,207
Obligations of U.S. states and political subdivisions [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	91,037	66,309
Investment Securities Available-for-Sale: Unrealized Gains	5,222	2,900
Investment Securities Available-for-Sale: Unrealized Losses	(7)	(36)
Investment Securities Available-for-Sale: Fair Value	96,252	69,173
Investment Securities Held-to-Maturity: Amortized Cost	39,242	37,695
Investment Securities Held-to-Maturity: Unrealized Gains	4,193	2,615
Investment Securities Held-to-Maturity: Fair Value	43,435	40,310
Trust preferred securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	18,113	20,567
Investment Securities Available-for-Sale: Unrealized Gains	118	14
Investment Securities Available-for-Sale: Unrealized Losses	(1,492)	(4,394)
Investment Securities Available-for-Sale: Fair Value	16,739	16,187
Corporate bonds and notes [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	228,865	175,812
Investment Securities Available-for-Sale: Unrealized Gains	8,262	1,382
Investment Securities Available-for-Sale: Unrealized Losses	(412)	(4,077)
Investment Securities Available-for-Sale: Fair Value	236,715	173,117
Asset-backed securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	19,609	7,614
Investment Securities Available-for-Sale: Unrealized Gains	253	52
Investment Securities Available-for-Sale: Unrealized Losses		(13)
Investment Securities Available-for-Sale: Fair Value	19,862	7,653
Collateralized mortgage obligations [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	2,673	3,226
Investment Securities Available-for-Sale: Unrealized Losses	(736)	(1,327)
Investment Securities Available-for-Sale: Fair Value	1,937	1,899
Certificates of Deposit [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	3,005
Investment Securities Available-for-Sale: Unrealized Gains	28
Investment Securities Available-for-Sale: Unrealized Losses	(6)
Investment Securities Available-for-Sale: Fair Value	3,027
Equity securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	635	535
Investment Securities Available-for-Sale: Unrealized Gains	7
Investment Securities Available-for-Sale: Unrealized Losses	(186)	(273)
Investment Securities Available-for-Sale: Fair Value	456	262
Other securities [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Amortized cost	15,994	5,882
Investment Securities Available-for-Sale: Unrealized Gains	68	21
Investment Securities Available-for-Sale: Unrealized Losses	(15)	(20)
Investment Securities Available-for-Sale: Fair Value	$ 16,047	$ 5,883