Short Term Borrowings (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Lines Of Credit Facility
Established Lines at Year-End	$ 60,000	$ 60,000
Maximum Amount Outstanding	29,000	24,300
Weighted average daily amounts of borrowings outstanding	25,122	19,629
Notes Payable	$ 27,950	$ 24,250
Weighted average interest rates on line of credit facility (As a percentage)	1.43%	1.44%
Weighted Average Interest Rate at Year-End	1.40%	1.33%