Investment Securities (Continuous Unrealized Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012 securities	Dec. 31, 2011 securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, estimated fair value	$ 99,220	$ 137,577
Less than 12 months, gross unrealized losses	1,106	2,193
12 months or more, estimated fair value	12,594	16,552
12 months or more, gross unrealized losses	92	180
Total, estimated fair value	111,814	154,129
Total, gross unrealized losses	1,198	2,373
Less than 12 months, number of securities	10	32
12 months or more, number of securities	3	7
Obligations of U.S. government sponsored agencies [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, estimated fair value		21,248
Less than 12 months, gross unrealized losses		151
12 months or more, estimated fair value		0
12 months or more, gross unrealized losses		0
Total, estimated fair value		21,248
Total, gross unrealized losses		151
Obligations of states and political subdivisions [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, estimated fair value		1,907
Less than 12 months, gross unrealized losses		1
12 months or more, estimated fair value		0
12 months or more, gross unrealized losses		0
Total, estimated fair value		1,907
Total, gross unrealized losses		1
Residential mortgage-backed securities - GSE [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, estimated fair value	43,983	89,730
Less than 12 months, gross unrealized losses	167	1,042
12 months or more, estimated fair value	12,594	16,552
12 months or more, gross unrealized losses	92	180
Total, estimated fair value	56,577	106,282
Total, gross unrealized losses	259	1,222
Residential mortgage-backed securities - private [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, estimated fair value	13,061	21,519
Less than 12 months, gross unrealized losses	769	967
12 months or more, estimated fair value	0	0
12 months or more, gross unrealized losses	0	0
Total, estimated fair value	13,061	21,519
Total, gross unrealized losses	769	967
Commercial mortgage-backed securities - private [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, estimated fair value	5,339
Less than 12 months, gross unrealized losses	15
12 months or more, estimated fair value	0
12 months or more, gross unrealized losses	0
Total, estimated fair value	5,339
Total, gross unrealized losses	15
Corporate notes [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, estimated fair value	36,837	3,173
Less than 12 months, gross unrealized losses	155	32
12 months or more, estimated fair value	0	0
12 months or more, gross unrealized losses	0	0
Total, estimated fair value	36,837	3,173
Total, gross unrealized losses	$ 155	$ 32