Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013 holding	Dec. 31, 2012 holding
Summary of gross unrealized losses and fair value of investments
No of holdings	71	38
Fair value, less than 12 months	$ 262,002	$ 50,344
Unrealized losses, less than 12 months	(9,359)	(225)
Fair value, 12 months or longer	5,920	2,069
Unrealized losses, 12 months or longer	(2,141)	(2,415)
Fair value, Total	267,922	52,413
Unrealized losses, Total	11,500	2,640
U. S. Government Agency Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	2
Fair value, less than 12 months	19,599
Unrealized losses, less than 12 months	(449)
Fair value, 12 months or longer
Unrealized losses, 12 months or longer
Fair value, Total	19,599
Unrealized losses, Total	449
Agency Mortgage-Backed Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	31	17
Fair value, less than 12 months	84,934	23,814
Unrealized losses, less than 12 months	(2,893)	(114)
Fair value, 12 months or longer	3,431	0
Unrealized losses, 12 months or longer	(222)	0
Fair value, Total	88,365	23,814
Unrealized losses, Total	3,115	114
Agency Collateralized Mortgage Obligations [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	15	2
Fair value, less than 12 months	149,561	17,677
Unrealized losses, less than 12 months	(5,736)	(39)
Fair value, 12 months or longer		0
Unrealized losses, 12 months or longer		0
Fair value, Total	149,561	17,677
Unrealized losses, Total	5,736	39
Pooled Trust Preferred Securities Issued by Banks and Insurers [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	2	2
Fair value, less than 12 months	0
Unrealized losses, less than 12 months	0
Fair value, 12 months or longer	2,343	2,069
Unrealized losses, 12 months or longer	(1,900)	(2,415)
Fair value, Total	2,343	2,069
Unrealized losses, Total	1,900	2,415
Single Trust Preferred Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	2	2
Fair value, less than 12 months	2,173	2,240
Unrealized losses, less than 12 months	49	15
Fair value, 12 months or longer	0	0
Unrealized losses, 12 months or longer	0	0
Fair value, Total	2,173	2,240
Unrealized losses, Total	(49)	(15)
Marketable Equity Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings	19	15
Fair value, less than 12 months	5,735	6,613
Unrealized losses, less than 12 months	(232)	(57)
Fair value, 12 months or longer	146
Unrealized losses, 12 months or longer	(19)
Fair value, Total	5,881	6,613
Unrealized losses, Total	$ 251	$ 57