Loans Acquired impaired and non-impaired loans (Details) (USD $) In Thousands, unless otherwise specified	Apr. 12, 2013
Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	$ 824,608
Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	3,799,685
Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	4,624,293
C&I | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	95,188
C&I | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	1,664,912
C&I | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	1,760,100
CRE | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	380,039
CRE | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	359,066
CRE | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	739,105
Construction | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	13,399
Construction | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	17,135
Construction | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	30,534
Residential mortgages | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	233,007
Residential mortgages | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	279,736
Residential mortgages | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	512,743
Installment | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	54,377
Installment | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	1,165,235
Installment | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	1,219,612
Home equity lines | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	48,598
Home equity lines | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	313,601
Home equity lines | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	362,199
Consumer Loan | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	335,982
Consumer Loan | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	1,758,572
Consumer Loan | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	2,094,554
Commercial Loan | Acquired Impaired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	488,626
Commercial Loan | Acquired performing loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	2,041,113
Commercial Loan | Acquired Loans
Acquired Impaired and Non-Impaired Loans at Acquisition Date [Line Items]
Loans	$ 2,529,739