Borrowings (Federal Home Loan Bank Advances Maturity Schedule) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Federal Home Loan Bank advances	$ 406,297	$ 288,082
Federal Home Loan Bank of Boston [Member]
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Scheduled Maturity, next 12 months	201,569
Scheduled Maturity, year two	63,130
Scheduled Maturity, year three	41,045
Scheduled Maturity, year four	64,803
Scheduled Maturity, year five	27,243
Scheduled Maturity, thereafter	8,507
Federal Home Loan Bank advances	$ 406,297	$ 288,100
Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate of Amounts Due [Abstract]
Weighted Average Rate, next 12 months	0.40%
Weighted Average Rate, year two	2.31%
Weighted Average Rate, year three	3.16%
Weighted Average Rate, year four	3.85%
Weighted Average Rate, year five	4.31%
Weighted Average Rate, thereafter	5.08%
Weighted Average Rate, Total	1.89%

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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The weighted average interest rate applicable to the Federal Home Loan Bank advances which are due after five years of the Balance Sheet date.

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The weighted average interest rate applicable to the Federal Home Loan Bank advances which are due from four to five years of the Balance Sheet date.

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The weighted average interest rate applicable to the Federal Home Loan Bank advances which are due within one year of the Balance Sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(3)(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 3

-Section VII.3

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The weighted average interest rate applicable to the Federal Home Loan Bank advances which are due from one to two years of the Balance Sheet date.

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The weighted average interest rate applicable to the Federal Home Loan Bank advances which are due from three to four years of the Balance Sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.14)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 3

-Section VII

-Paragraph 3

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The weighted average interest rate applicable to the Federal Home Loan Bank advances which are due from two to three years of the Balance Sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, Total

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