Securities (Unrealized Loss NOT deemed to be OTTI) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014 holding	Dec. 31, 2013 holding
Summary of gross unrealized losses and fair value of investments
No of holdings	114	221
Fair value, less than 12 months	$ 114,374	$ 433,230
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(540)	(13,520)
Fair value, 12 months or longer	156,164	10,928
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(8,297)	(2,490)
Fair value, Total	270,538	444,158
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss	(8,837)	(16,010)
U. S. Government Agency Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	25	39
Fair value, less than 12 months	33,836	39,950
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(93)	(885)
Fair value, 12 months or longer
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months
Fair value, Total	33,836	39,950
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss	(93)	(885)
Agency mortgage-backed securities
Summary of gross unrealized losses and fair value of investments
No of holdings	54	124
Fair value, less than 12 months	44,458	202,004
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(60)	(5,217)
Fair value, 12 months or longer	45,437	5,108
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(1,511)	(372)
Fair value, Total	89,895	207,112
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss	(1,571)	(5,589)
Agency Collateralized Mortgage Obligations [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	15	19
Fair value, less than 12 months	34,062	183,721
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(345)	(7,278)
Fair value, 12 months or longer	104,095	0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(5,092)
Fair value, Total	138,157	183,721
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss	(5,437)	(7,278)
US States and Political Subdivisions Debt Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings		13
Fair value, less than 12 months		3,838
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months		(28)
Fair value, 12 months or longer		0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months
Fair value, Total		3,838
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss		(28)
Single issuer trust preferred securities issued by banks
Summary of gross unrealized losses and fair value of investments
No of holdings	1	2
Fair value, less than 12 months	1,083	1,341
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(16)	(22)
Fair value, 12 months or longer	0	0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	0
Fair value, Total	1,083	1,341
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss	(16)	(22)
Pooled trust preferred securities issued by banks and insurers
Summary of gross unrealized losses and fair value of investments
No of holdings	2	2
Fair value, less than 12 months	0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months
Fair value, 12 months or longer	2,580	2,300
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(1,512)	(1,913)
Fair value, Total	2,580	2,300
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss	(1,512)	(1,913)
Equity securities
Summary of gross unrealized losses and fair value of investments
No of holdings	17	22
Fair value, less than 12 months	935	2,376
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(26)	(90)
Fair value, 12 months or longer	4,052	3,520
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(182)	(205)
Fair value, Total	4,987	5,896
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position aggregate loss	$ (208)	$ (295)