Investments (Amortized Cost and Aggregate Fair Value of Debt Securities, by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investments [Abstract]
Available-for-sale Securities, Due in one year or less, Amortized Cost	$ 1,620
Available-for-sale Securities, Due in one year or less, Fair Value	1,685
Available-for-sale Securities, Due after one year through five years, Amortized Cost	13,388
Available-for-sale Securities, Due after one year through five years, Fair Value	14,612
Available-for-sale Securities, Due after five years through ten years, Amortized Cost	22,414
Available-for-sale Securities, Due after five years through ten years, Fair Value	23,943
Available-for-sale Securities, Due after ten years, Amortized Cost	34,837
Available-for-sale Securities, Due after ten years, Fair Value	36,553
Available-for-sale securities, Amortized Cost	72,259	69,980
Available-for-sale Securities, Fair Value	76,793
Held-to-maturity Securities, Due in one year or less, Amortized Cost	0
Held-to-maturity Securities, Due in one year or less, Fair Value	0
Held-to-maturity Securities, Due after one year through five years, Amortized Cost	164
Held-to-maturity Securities, Due after one year through five years, Fair Value	168
Held-to-maturity Securities, Due after five years through ten years, Amortized Cost	410
Held-to-maturity Securities, Due after five years through ten years, Fair Value	442
Held-to-maturity Securities, Due after ten years, Amortized Cost	1,175
Held-to-maturity Securities, Due after ten years, Fair Value	1,275
Held-to-maturity Securities, Amortized Cost	1,749	3,303
Held-to-maturity Securities, Fair Value	$ 1,885	$ 3,497