Borrowings (Certain Information of Federal Home Loan Bank of Boston Advances) (Details) (Federal Home Loan Bank of Boston [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Federal Home Loan Bank of Boston [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Average amount outstanding during the period	$ 13,901	$ 61,936	$ 36,870
Amount outstanding at end of period	0	40,500	102,500
Highest month end balance during period	$ 60,000	$ 102,929	$ 105,500
Weighted-average interest rate at end of period	0.00%	0.28%	0.18%
Weighted-average interest rate during the period	0.30%	0.27%	0.23%