Investment Securities (Contractual Maturities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Securities Available for Sale, Amortized Cost
Due in one year or less	$ 4,148
Due after one year through three years	31,547
Due after three years through five years	23,675
Due after five years through ten years	150,635
Due after ten years	525,384
Investment securities with no stated maturity	1,956
Total	737,345	164,553
Securities Available for Sale, Fair Value
Due in one year or less	4,171
Due after one year through three years	31,693
Due after three years through five years	24,104
Due after five years through ten years	151,946
Due after ten years	528,959
Investment securities with no stated maturity	1,973
Fair Value	742,846	163,134
Securities Held to Maturity, Amortized Cost
Due in one year or less	2,895
Due after one year through three years	4,336
Due after three years through five years	5,490
Due after five years through ten years	18,558
Due after ten years	4,535
Investment securities with no stated maturity	0
Total	35,814	36,154
Securities Held to Maturity, Fair Value
Due in one year or less	2,912
Due after one year through three years	4,385
Due after three years through five years	5,710
Due after five years through ten years	19,359
Due after ten years	4,508
Investment securities with no stated maturity	0
Total	$ 36,874	$ 36,340