Securities (Summary of Gross Unrealized Losses and Fair Value of the Investments with Unrealized Losses) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	$ 34,013	$ 242,695
Less than 12 Months Unrealized Losses	(276)	(2,023)
12 Months or More Fair Value	19,844	2,116
12 Months or More Unrealized Losses	(190)	(65)
Total Fair Value	53,857	244,811
Total Unrealized Losses	(466)	(2,088)
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	33,377	238,875
Less than 12 Months Unrealized Losses	(272)	(1,999)
12 Months or More Fair Value	18,445	196
12 Months or More Unrealized Losses	(151)	(1)
Total Fair Value	51,822	239,071
Total Unrealized Losses	(423)	(2,000)
State and Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	636	3,820
Less than 12 Months Unrealized Losses	(4)	(24)
12 Months or More Fair Value	424	950
12 Months or More Unrealized Losses	(14)	(34)
Total Fair Value	1,060	4,770
Total Unrealized Losses	(18)	(58)
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Fair Value	0	0
Less than 12 Months Unrealized Losses	0	0
12 Months or More Fair Value	975	970
12 Months or More Unrealized Losses	(25)	(30)
Total Fair Value	975	970
Total Unrealized Losses	$ (25)	$ (30)