Securities, Available-for-sale (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Available-for-sale securities, continuous unrealized loss position [Abstract]
Investments with an Unrealized Loss of less than 12 months, Fair Value	$ 73,648	$ 213,232
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	530	5,292
Investments with an Unrealized Loss of 12 months or longer, Fair Value	257,612	156,735
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	10,714	19,101
Total Investments with an Unrealized Loss, Fair Value	331,260	369,967
Total Investments with an Unrealized Loss, Unrealized Losses	11,244	24,393
US Treasury Securities [Member]
Available-for-sale securities, continuous unrealized loss position [Abstract]
Investments with an Unrealized Loss of less than 12 months, Fair Value	0	0
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	0	0
Investments with an Unrealized Loss of 12 months or longer, Fair Value	0	0
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	0	0
Total Investments with an Unrealized Loss, Fair Value	0	0
Total Investments with an Unrealized Loss, Unrealized Losses	0	0
U.S. Government Agency Securities [Member]
Available-for-sale securities, continuous unrealized loss position [Abstract]
Investments with an Unrealized Loss of less than 12 months, Fair Value	903	8,742
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	2	22
Investments with an Unrealized Loss of 12 months or longer, Fair Value	101,152	92,869
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	6,146	13,400
Total Investments with an Unrealized Loss, Fair Value	102,055	101,611
Total Investments with an Unrealized Loss, Unrealized Losses	6,148	13,422
Mortgage-backed Securities [Member]
Available-for-sale securities, continuous unrealized loss position [Abstract]
Investments with an Unrealized Loss of less than 12 months, Fair Value	69,147	157,262
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	515	3,913
Investments with an Unrealized Loss of 12 months or longer, Fair Value	109,845	42,903
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	3,735	4,889
Total Investments with an Unrealized Loss, Fair Value	178,992	200,165
Total Investments with an Unrealized Loss, Unrealized Losses	4,250	8,802
State and Municipal Securities [Member]
Available-for-sale securities, continuous unrealized loss position [Abstract]
Investments with an Unrealized Loss of less than 12 months, Fair Value	3,098	46,282
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	13	1,351
Investments with an Unrealized Loss of 12 months or longer, Fair Value	31,228	3,798
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	683	555
Total Investments with an Unrealized Loss, Fair Value	34,326	50,080
Total Investments with an Unrealized Loss, Unrealized Losses	696	1,906
Asset-backed Securities [Member]
Available-for-sale securities, continuous unrealized loss position [Abstract]
Investments with an Unrealized Loss of less than 12 months, Fair Value	0	0
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	0	0
Investments with an Unrealized Loss of 12 months or longer, Fair Value	15,230	17,006
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	150	255
Total Investments with an Unrealized Loss, Fair Value	15,230	17,006
Total Investments with an Unrealized Loss, Unrealized Losses	150	255
Corporate Notes [Member]
Available-for-sale securities, continuous unrealized loss position [Abstract]
Investments with an Unrealized Loss of less than 12 months, Fair Value	500	946
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	0	6
Investments with an Unrealized Loss of 12 months or longer, Fair Value	157	159
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	0	2
Total Investments with an Unrealized Loss, Fair Value	657	1,105
Total Investments with an Unrealized Loss, Unrealized Losses	$ 0	$ 8