Securities (Amortized Cost and Fair Value of Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Securities Available-for-Sale: Amortized cost
Due in one year or less	$ 4,582
Due after one year through five years	12,828
Due after five years through ten years	55,349
Due after ten years	27,208
Total	614,402	571,058
Securities Available-for-Sale, Fair Value
Due in one year or less	4,616
Due after one year through five years	13,138
Due after five years through ten years	55,605
Due after ten years	27,767
Total	612,569	587,602
Securities Held-to-Maturity, Carrying Amount
Due in one year or less	0
Due after one year through five years	268
Due after five years through ten years	0
Due after ten years	0
Total	268	346
Securities Held-to-Maturity, Fair Value
Due in one year or less	0
Due after one year through five years	271
Due after five years through ten years	0
Due after ten years	0
Fair Value	271	351
Mortgage-backed Securities - Residential [Member]
Securities Available-for-Sale: Amortized cost
Available-for-Sale, amortized cost	513,751
Total	513,751	475,452
Securities Available-for-Sale, Fair Value
Available-for-Sale, Fair Value	510,679
Total	510,679	486,912
Equity Securities [Member]
Securities Available-for-Sale: Amortized cost
Available-for-Sale, amortized cost	684
Total	684	684
Securities Available-for-Sale, Fair Value
Available-for-Sale, Fair Value	764
Total	$ 764	$ 733