Securities (Amortized Cost and Fair Value of Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Securities Available-for-Sale: Amortized cost
Due in one year or less	$ 2,855
Due after one year through five years	11,966
Due after five years through ten years	60,770
Due after ten years	40,196
Total	612,600	571,058
Securities Available-for-Sale, Fair Value
Due in one year or less	2,878
Due after one year through five years	12,237
Due after five years through ten years	61,075
Due after ten years	40,868
Total	608,653	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	496,129
Total	496,129	475,452
Securities Available-for-Sale, Fair Value
Available-for-Sale, Fair Value	490,569
Total	490,569	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	1,026
Total	$ 1,026	$ 733