Fair Value Measurements and Fair Value of Financial Instruments (Schedule of Placement of Carrying Amount and Fair Value in Heirarchy) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	$ 73,668	$ 111,101
Interest bearing deposits with banks	12,000	0
Investment securities held-to-maturity	62,997	72,233
Restricted investment in bank stocks	9,139	9,233
Accrued interest receivable	6,465	6,219
Short-term Borrowings	107
Subordinated debentures	5,155	5,155
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	73,668	111,101
Interest bearing deposits with banks	12,000
Investment securities held-to-maturity	66,562		74,922
Restricted investment in bank stocks	9,139		9,233
Net loans (including loans held for sale)	803,952		752,252
Accrued interest receivable	6,465		6,219
Non interest-bearing deposits	181,282		167,164
Interest-bearing deposits	994,379		928,777
Short-term Borrowings	107
Long-term borrowings	179,241		175,933
Subordinated debentures	5,184		5,159
Accrued interest payable	912		992
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	73,668	111,101
Interest bearing deposits with banks	12,000
Restricted investment in bank stocks	9,139		9,233
Net loans (including loans held for sale)	501		1,029
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities held-to-maturity	66,562		74,922
Accrued interest receivable	4,302		3,894
Non interest-bearing deposits	181,282		167,164
Interest-bearing deposits	994,379		928,777
Short-term Borrowings	107
Long-term borrowings	179,241		175,933
Subordinated debentures	5,184		5,159
Accrued interest payable	912		992
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans (including loans held for sale)	803,451		751,223
Accrued interest receivable	$ 2,163		$ 2,325