Loans Receivable and Credit Quality Loans by Credit Quality Indicator (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 5,112,459	$ 4,814,136
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,938,369	4,578,523
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	87,313	84,739
Accruing Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	42,015	90,129
Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	44,762	60,745
Commercial Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	866,053	806,326
Commercial Loan [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	849,535	779,236
Commercial Loan [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,857	13,691	[1]
Commercial Loan [Member] | Accruing Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,177	9,062
Commercial Loan [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,484	4,337
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,813,394	1,691,350
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,709,265	1,531,701
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	60,305	54,000	[1]
Commercial Real Estate Portfolio Segment [Member] | Accruing Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	19,857	63,953
Commercial Real Estate Portfolio Segment [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	23,967	41,696
Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	153,917	137,570
Construction Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	128,667	110,940
Construction Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	21,172	17,048
Construction Loans [Member] | Accruing Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	589	7,369
Construction Loans [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,489	2,213
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,032,294	1,906,089
Residential Portfolio Segment [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,006,707	1,886,273
Residential Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Residential Portfolio Segment [Member] | Accruing Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,810	8,072
Residential Portfolio Segment [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,777	11,744
Home Equity Line of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	113,660	123,551
Home Equity Line of Credit [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	112,065	121,218
Home Equity Line of Credit [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Home Equity Line of Credit [Member] | Accruing Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	575	1,673
Home Equity Line of Credit [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,020	660
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	133,141	149,250
Consumer Portfolio Segment [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	132,130	149,155
Consumer Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	979	0
Consumer Portfolio Segment [Member] | Accruing Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7	0
Consumer Portfolio Segment [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	25	95
Transferred to Held For Sale Pacific Northwest Transaction [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Number of Loans		1
Transferred to Held For Sale Pacific Northwest Transaction [Member] | Commercial Loan [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		900
Number of Loans		5
Transferred to Held For Sale Pacific Northwest Transaction [Member] | Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		$ 3,000
Number of Loans		3

[1] Does not include five commercial and industrial special mention loans totaling $0.9 million and three commercial real estate special mention loans totaling $3.0 million in loans held for sale as of December 31, 2012.