Loans Receivable and Allowance for Loan Losses (Details 9) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Credit quality indicators
Total loans	$ 5,806,291	$ 5,702,480
Pass
Credit quality indicators
Total loans	5,510,838	5,370,444
Special mention
Credit quality indicators
Total loans	58,602	81,207
Substandard
Credit quality indicators
Total loans	232,342	244,951
Doubtful
Credit quality indicators
Total loans	3,188	4,829
Loss
Credit quality indicators
Total loans	1,321	1,049
Special mention or substandard | Minimum
Credit quality indicators
Total loans	1,000
Personal Banking
Credit quality indicators
Total loans	3,795,291	3,727,653
Personal Banking | Pass
Credit quality indicators
Total loans	3,766,574	3,698,098
Personal Banking | Substandard
Credit quality indicators
Total loans	27,396	28,458
Personal Banking | Doubtful
Credit quality indicators
Total loans		48
Personal Banking | Loss
Credit quality indicators
Total loans	1,321	1,049
Personal Banking | Residential mortgage loans
Credit quality indicators
Total loans	2,483,004	2,415,649
Personal Banking | Residential mortgage loans | Pass
Credit quality indicators
Total loans	2,464,057	2,395,809
Personal Banking | Residential mortgage loans | Substandard
Credit quality indicators
Total loans	17,626	18,743
Personal Banking | Residential mortgage loans | Doubtful
Credit quality indicators
Total loans		48
Personal Banking | Residential mortgage loans | Loss
Credit quality indicators
Total loans	1,321	1,049
Personal Banking | Home equity loans
Credit quality indicators
Total loans	1,083,939	1,083,654
Personal Banking | Home equity loans | Pass
Credit quality indicators
Total loans	1,075,595	1,075,200
Personal Banking | Home equity loans | Substandard
Credit quality indicators
Total loans	8,344	8,454
Personal Banking | Other consumer loans
Credit quality indicators
Total loans	228,348	228,350
Personal Banking | Other consumer loans | Pass
Credit quality indicators
Total loans	226,922	227,089
Personal Banking | Other consumer loans | Substandard
Credit quality indicators
Total loans	1,426	1,261
Business Banking
Credit quality indicators
Total loans	2,011,000	1,974,827
Business Banking | Pass
Credit quality indicators
Total loans	1,744,264	1,672,346
Business Banking | Special mention
Credit quality indicators
Total loans	58,602	81,207
Business Banking | Substandard
Credit quality indicators
Total loans	204,946	216,493
Business Banking | Doubtful
Credit quality indicators
Total loans	3,188	4,781
Business Banking | Commercial real estate loans
Credit quality indicators
Total loans	1,608,399	1,585,833
Business Banking | Commercial real estate loans | Pass
Credit quality indicators
Total loans	1,398,652	1,352,118
Business Banking | Commercial real estate loans | Special mention
Credit quality indicators
Total loans	46,557	68,130
Business Banking | Commercial real estate loans | Substandard
Credit quality indicators
Total loans	161,906	163,751
Business Banking | Commercial real estate loans | Doubtful
Credit quality indicators
Total loans	1,284	1,834
Business Banking | Commercial loans
Credit quality indicators
Total loans	402,601	388,994
Business Banking | Commercial loans | Pass
Credit quality indicators
Total loans	345,612	320,228
Business Banking | Commercial loans | Special mention
Credit quality indicators
Total loans	12,045	13,077
Business Banking | Commercial loans | Substandard
Credit quality indicators
Total loans	43,040	52,742
Business Banking | Commercial loans | Doubtful
Credit quality indicators
Total loans	$ 1,904	$ 2,947