Fair Value Measurements (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	$ 29,905		$ 40,381
Loans, net of allowance of loan losses	2,434,998		2,263,130
Loan servicing rights	2,698		1,110		765	757
Time deposits	790,762		870,232
FHLBB advances	288,082		361,172
Junior subordinated debentures	22,681		32,991
Loan servicing rights reserve	69		165
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	29,905		40,381
Loans, net of allowance of loan losses	2,434,998		2,263,130
Loan servicing rights	2,698	[1]	1,110	[2]
Time deposits	790,762		870,232
FHLBB advances	288,082		361,172
Junior subordinated debentures	22,681		32,991
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	29,865		41,420
Loans, net of allowance of loan losses	2,479,527		2,350,153
Loan servicing rights	2,767	[1]	1,275	[2]
Time deposits	797,748		879,705
FHLBB advances	308,317		392,805
Junior subordinated debentures	16,282		23,371
Level 1 [Member] | Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	0		0
Loans, net of allowance of loan losses	0		0
Loan servicing rights	0	[1]	0	[2]
Time deposits	0		0
FHLBB advances	0		0
Junior subordinated debentures	0		0
Level 2 [Member] | Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	29,865		41,420
Loans, net of allowance of loan losses	0		0
Loan servicing rights	0	[1]	0	[2]
Time deposits	797,748		879,705
FHLBB advances	308,317		392,805
Junior subordinated debentures	16,282		23,371
Level 3 [Member] | Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	0		0
Loans, net of allowance of loan losses	2,479,527		2,350,153
Loan servicing rights	2,767	[1]	1,275	[2]
Time deposits	0		0
FHLBB advances	0		0
Junior subordinated debentures	$ 0		$ 0

[1] The carrying value of loan servicing rights is net of $69 thousand in reserves as of December 31, 2013. The estimated fair value does not include such adjustment.

[2] The carrying value of loan servicing rights is net of $165 thousand in reserves as of December 31, 2012. The estimated fair value does not include such adjustment.