Investments (Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Investments [Abstract]
Securities Available-for-Sale, Due in one year or less, Cost	$ 6,390
Securities Available-for-Sale, Due after one year through five years, Cost	27,166
Securities Available-for-Sale, Due after five years through ten years, Cost	49,244
Securities Available-for-Sale, Due after ten years, Cost	253,427
Securities Available-for-Sale, Cost, Total	336,227
Securities Available-for-Sale, Due in one year or less, Estimated Fair Value	6,433
Securities Available-for-Sale, Due after one year through five years, Estimated Fair Value	27,635
Securities Available-for-Sale, Due after five years through ten years, Estimated Fair Value	51,234
Securities Available-for-Sale, Due after ten years, Estimated Fair Value	256,240
Securities Available-for-Sale, Estimated Fair Value, Total	341,542
Securities Held-to-Maturity, Due after ten years, Cost	8,383
Securities Held-to-Maturity, Cost, Total	8,383
Securities Held-to-Maturity, Due after ten years, Estimated Fair Value	8,921
Securities Held-to-Maturity, Estimated Fair Value, Total	$ 8,921