Investment Securities, Contract Maturity (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Amortized Cost [Abstract]
Within One Year	$ 27,372
After One Year Through Five Years	44,209
After Five Years Through Ten Years	3,244
After Ten Years	0
Amortized cost, before single maturity date	74,825
Investment Securities Not Due at a Single Maturity Date - Mortgage-backed Securities	323,518
Amortized cost, Total	398,343
Fair/Book Value [Abstract]
Within One Year	27,420
After One Year Through Five Years	44,582
After Five Years Through Ten Years	3,395
After Ten Years	0
Fair/Book Value, before single maturity date	75,397
Investment Securities Not Due at a Single Maturity Date - Mortgage-backed Securities	326,335
Fair/Book Value, Total	401,732	404,639	475,414
Amortized Cost [Abstract]
Within One Year	1,930
After One Year Through Five Years	18,971
After Five Years Through Ten Years	18,360
After Ten Years	31,079
Amortized cost, before single maturity date	70,340
Investment Securities Not Due at a Single Maturity Date - Mortgage-backed Securities	0
Amortized cost, Total	70,340	68,505	67,059
Fair Value [Abstract]
Within One Year	1,937
After One Year Through Five Years	19,299
After Five Years Through Ten Years	18,606
After Ten Years	31,091
Fair/Book Value, before single maturity date	70,933
Investment Securities Not Due at a Single Maturity Date - Mortgage-backed Securities	0
Fair Value	$ 70,933