Borrowed Funds (Summary of Short Term Borrowings) (Details) (USD $)
In Thousands, unless otherwise specified
6 Months Ended 12 Months Ended
Jun. 30, 2012
Dec. 31, 2011
Borrowed Funds [Abstract]    
Outstanding at end of period $ 28,902 $ 36,868
Weighted average interest rate at end of period 0.68% 0.64%
Maximum amount outstanding as of any month end 36,627 51,403
Average amount outstanding $ 35,347 $ 41,728
Approximate weighted average rate during the period 0.55% 0.56%