Loans, Allowance for Loan Losses and Credit Quality Loans, Allowance for Loan Losses and Credit Quality (Details 13) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Nov. 09, 2012	Dec. 31, 2011
Loans, Allowance for Loan Losses and Credit Quality [Abstract]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield	$ 2,526		$ 2,464	$ 3,095	$ 0
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion	(377)	(903)
Certainloansacquiredintransfernotaccountedforasdebtsecuritiesaccretableyieldadjustmentchangesinexpectedcashflow	439
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, Reclassifications from Nonaccretable Difference			$ 272

The aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan for loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References+ Details

Change in the estimate of cash flows expected to be collected, after acquisition of a loan, which results in an increase in accretable yield (for example, if actual cash flows are significantly greater than previously expected). This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References+ Details

- Definition

The current period recognition due to accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References+ Details