Schedule of Accumulated Other Comprehensive Loss (Tables) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 12 Months Ended
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Balance $ (20,716) $ (20,861) $ (20,962) $ (19,821)
Net gain/(loss) during period 145 101 (1,141)  
Investment securities- with OTTI [Member]
       
Balance (10,597) (10,376) (10,572) (10,825)
Net gain/(loss) during period (221) 196 253  
Investment securities- all other [Member]
       
Balance (2,409) (2,755) (2,633) (3,956)
Net gain/(loss) during period 346 (122) 1,323  
Cash Flow Hedge (OCI) [Member]
       
Balance (569) (589) (616) (496)
Net gain/(loss) during period 20 27 (120)  
Pension Plan [Member]
       
Balance (6,945) (6,945) (6,945) (4,203)
Net gain/(loss) during period 0 0 (2,742)  
SERP [Member]
       
Balance (196) (196) (196) (341)
Net gain/(loss) during period $ 0 $ 0 $ 145