Derivative Financial Instruments (Balance sheet category and fair values of derivative insturments (cash flow hedges)) (Details) (Other Liabilities, USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Interest Rate Swap 1
Derivatives, Fair Value [Line Items]
Notional amount	$ 12,688	$ 13,002
Fair Value	(645)	(711)
Receive Rate	2.953%	2.961%
Weighted Average Pay Rate	5.14%	5.14%
Interest Rate Swap 2
Derivatives, Fair Value [Line Items]
Notional amount	25,000	25,000
Fair Value	(565)	(708)
Receive Rate	0.28%	0.308%
Weighted Average Pay Rate	2.58%	2.58%
Interest Rate Swap 3
Derivatives, Fair Value [Line Items]
Notional amount	20,000	20,000
Fair Value	(2,055)	(2,186)
Receive Rate	0.287%	0.311%
Weighted Average Pay Rate	3.22%	3.22%
Interest Rate Swap 4
Derivatives, Fair Value [Line Items]
Notional amount	20,000	20,000
Fair Value	$ (2,773)	$ (3,020)
Receive Rate	0.305%	0.351%
Weighted Average Pay Rate	3.355%	3.355%