Loans (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	$ 103,270	$ 120,985
Commercial Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	73,255	92,296
Residential mortgage Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	25,043	21,898
Consumer loan [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	4,972	6,791
Originated loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	83,307	75,699
Originated loans [Member] | Commercial Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	55,046	50,379
Originated loans [Member] | Residential mortgage Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	24,406	18,699
Originated loans [Member] | Consumer loan [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	3,855	6,621
Acquired loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	1,117	0
Acquired loans [Member] | Commercial Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	0	0
Acquired loans [Member] | Residential mortgage Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	0	0
Acquired loans [Member] | Consumer loan [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	1,117	0
Covered loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	18,846	45,286
Covered loans [Member] | Commercial Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	18,209	41,917
Covered loans [Member] | Residential mortgage Loans [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	637	3,199
Covered loans [Member] | Consumer loan [Member]
Composition of Non-Accrual Loans by Portfolio Segment
Non-accrual loans	$ 0	$ 170