Securities, Available-for-sale (Details) (USD $) In Thousands, unless otherwise specified	Sep. 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	$ 93,637	$ 213,232
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	476	5,292
Investments with an Unrealized Loss of 12 months or longer, Fair Value	242,460	156,735
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	10,321	19,101
Total Investments with an Unrealized Loss, Fair Value	336,097	369,967
Total Investments with an Unrealized Loss, Unrealized Losses	10,797	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	3,097	8,742
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	5	22
Investments with an Unrealized Loss of 12 months or longer, Fair Value	101,336	92,869
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	5,964	13,400
Total Investments with an Unrealized Loss, Fair Value	104,433	101,611
Total Investments with an Unrealized Loss, Unrealized Losses	5,969	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	89,115	157,262
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	457	3,913
Investments with an Unrealized Loss of 12 months or longer, Fair Value	104,285	42,903
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	3,809	4,889
Total Investments with an Unrealized Loss, Fair Value	193,400	200,165
Total Investments with an Unrealized Loss, Unrealized Losses	4,266	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	1,175	46,282
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	14	1,351
Investments with an Unrealized Loss of 12 months or longer, Fair Value	22,918	3,798
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	422	555
Total Investments with an Unrealized Loss, Fair Value	24,093	50,080
Total Investments with an Unrealized Loss, Unrealized Losses	436	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	13,766	17,006
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	125	255
Total Investments with an Unrealized Loss, Fair Value	13,766	17,006
Total Investments with an Unrealized Loss, Unrealized Losses	125	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	250	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	155	159
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	1	2
Total Investments with an Unrealized Loss, Fair Value	405	1,105
Total Investments with an Unrealized Loss, Unrealized Losses	$ 1	$ 8