Investment Securities (Held-to-maturity Securities with Unrealized Loss) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012 securities	Dec. 31, 2011 securities
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	$ 0	$ 6,416
Less than 12 months, unrealized loss	0	88
Less than 12 months, no. of securities	0	1
12 months or more, fair value	0	0
12 months or more, unrealized loss	0	0
12 months or more, no. of securities	0	0
Total fair value	0	6,416
Total unrealized loss	0	88
States and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	0	0
Less than 12 months, unrealized loss	0	0
Less than 12 months, no. of securities	0	0
12 months or more, fair value	0	0
12 months or more, unrealized loss	0	0
12 months or more, no. of securities	0	0
Total fair value	0	0
Total unrealized loss	0	0
Residential mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	0	6,416
Less than 12 months, unrealized loss	0	88
Less than 12 months, no. of securities	0	1
12 months or more, fair value	0	0
12 months or more, unrealized loss	0	0
12 months or more, no. of securities	0	0
Total fair value	0	6,416
Total unrealized loss	$ 0	$ 88