Long-Term Borrowings (Minimum Annual Retirements of Long-Term Borrowings) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Aggregate minimum annual retirements of long-term borrowings in future periods:
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 6,996
Long-term Debt, Maturities, Repayments of Principal in Year Two	6,498
Long-term Debt, Maturities, Repayments of Principal in Year Three	6,250
Long-term Debt, Maturities, Repayments of Principal in Year Four	6,046
Long-term Debt, Maturities, Repayments of Principal in Year Five	5,881
Thereafter, Balance	97,152
Long-term borrowings	$ 128,823	$ 142,312
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months, Weighted Average Interest Rate	3.76%
Long-term Debt, Maturities, Repayments of Principal in Year Three, Weighted Average Interest Rate	3.73%
Long-term Debt, Maturities, Repayments of Principal in Year Three, Weighted Average Interest Rate	3.74%
Long-term Debt, Maturities, Repayments of Principal in Year Four, Weighted Average Interest Rate	3.75%
Long-term Debt, Maturities, Repayments of Principal in Year Five, Weighted Average Interest Rate	3.76%
Thereafter, Weighted-Average Rate	3.47%
Total long-term borrowings, Weighted-Average Rate	3.54%	3.38%