Securities, Available-for-sale (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 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	$ 99,514	$ 213,232
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	431	5,292
Investments with an Unrealized Loss of 12 months or longer, Fair Value	232,495	156,735
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	5,822	19,101
Total Investments with an Unrealized Loss, Fair Value	332,009	369,967
Total Investments with an Unrealized Loss, Unrealized Losses	6,161	23,342
Total Securities Gross Unrealized Loss Accumulated In Investments	6,253	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	3,593	8,742
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	10	22
Investments with an Unrealized Loss of 12 months or longer, Fair Value	103,658	92,869
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	3,644	13,400
Total Investments with an Unrealized Loss, Fair Value	107,251	101,611
Total Investments with an Unrealized Loss, Unrealized Losses	3,654	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	91,410	157,262
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	405	3,913
Investments with an Unrealized Loss of 12 months or longer, Fair Value	102,892	42,903
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	1,835	4,889
Total Investments with an Unrealized Loss, Fair Value	194,302	200,165
Total Investments with an Unrealized Loss, Unrealized Losses	2,240	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	3,561	46,282
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	15	1,351
Investments with an Unrealized Loss of 12 months or longer, Fair Value	16,502	3,798
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	257	555
Total Investments with an Unrealized Loss, Fair Value	20,063	50,080
Total Investments with an Unrealized Loss, Unrealized Losses	180	856
Total Securities Gross Unrealized Loss Accumulated In Investments	272	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	9,289	17,006
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	85	255
Total Investments with an Unrealized Loss, Fair Value	9,289	17,006
Total Investments with an Unrealized Loss, Unrealized Losses	85	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	950	946
Investments with an Unrealized Loss of less than 12 months, Unrealized Losses	1	6
Investments with an Unrealized Loss of 12 months or longer, Fair Value	154	159
Investments with an Unrealized Loss of 12 months or longer, Unrealized Losses	1	2
Total Investments with an Unrealized Loss, Fair Value	1,104	1,105
Total Investments with an Unrealized Loss, Unrealized Losses	2	7
Total Securities Gross Unrealized Loss Accumulated In Investments		$ 8