Loans, Allowance for Loan Losses, and Credit Quality (Details 4) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Commercial loans by credit quality indicator
Commercial and industrial	$ 4,076,370	$ 3,724,736
Commercial real estate - owner occupied	1,116,815	1,086,829
Lease financing	62,750	58,194
Commercial and business lending	5,255,935	4,869,759
Commercial real estate - investor	2,810,521	2,563,767
Real estate construction	612,556	584,046
Commercial real estate lending	3,423,077	3,147,813
Total commercial	8,679,012	8,017,572
Pass [Member]
Commercial loans by credit quality indicator
Commercial and industrial	3,712,873	3,283,090
Commercial real estate - owner occupied	921,985	853,517
Lease financing	53,268	46,570
Commercial and business lending	4,688,126	4,183,177
Commercial real estate - investor	2,442,713	2,055,124
Real estate construction	539,433	494,839
Commercial real estate lending	2,982,146	2,549,963
Total commercial	7,670,272	6,733,140
Special Mention [Member]
Commercial loans by credit quality indicator
Commercial and industrial	167,223	209,713
Commercial real estate - owner occupied	45,790	53,090
Lease financing	898	822
Commercial and business lending	213,911	263,625
Commercial real estate - investor	87,224	135,668
Real estate construction	6,977	8,775
Commercial real estate lending	94,201	144,443
Total commercial	308,112	408,068
Potential Problem [Member]
Commercial loans by credit quality indicator
Commercial and industrial	121,764	153,306
Commercial real estate - owner occupied	108,508	136,366
Lease financing	324	158
Commercial and business lending	230,596	289,830
Commercial real estate - investor	142,453	230,206
Real estate construction	23,905	27,649
Commercial real estate lending	166,358	257,855
Total commercial	396,954	547,685
Impaired [Member]
Commercial loans by credit quality indicator
Commercial and industrial	74,510	78,627
Commercial real estate - owner occupied	40,532	43,856
Lease financing	8,260	10,644
Commercial and business lending	123,302	133,127
Commercial real estate - investor	138,131	142,769
Real estate construction	42,241	52,783
Commercial real estate lending	180,372	195,552
Total commercial	$ 303,674	$ 328,679

The total gross amount of commercial loans (money lent to commercial entities rather than consumers) made in the form of direct financing leases where the reporting entity (lessor) only recognizes interest revenue from the lease. It also includes the amount of lease financing arising from involvement with leveraged lease transactions where the Entity is in the position of long-term creditor.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Publisher SEC

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Leveraged Lease

-URI http://asc.fasb.org/extlink&oid=6516780

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

Reflects the sum of the gross carrying amounts of the various categories of unpaid commercial loans and leases receivable, primarily issued to businesses. Includes: (1) commercial and industrial loans, consisting of general purpose loans to entities involved in producing, transporting, or merchandising products sold in the course of commerce; (2) agricultural loans consisting of borrowings used to finance major equipment and machinery purchases and expenses, livestock or crop production (including fisheries), and to supplement working capital needs of an entity engaged in farming operations; (3) mortgage loans secured by a [legal] security interest in real property [commercial building or business real property]; (4) obligation in the form of [promissory] notes, used for the funding of construction projects; (5) interbank and other loans to financial institutions for the purpose of liquidity management on the part of the borrower; (6) draws against credit facilities provided to companies involved in mortgage banking activities (warehousing); (7) amounts lent to businesses engaged in international activities (trade financing); (8) lease financings; and (9) loans to governmental entities.

+ References+ Details

- Definition

Reflects the gross carrying amount of unpaid loans issued to nonfinancial and nonagricultural businesses for uses other than for real property.

+ References+ Details

- Definition

Reflects the gross carrying amount of unpaid loans that had been issued to businesses to construct a facility. Acquisition, development and construction (ADC) loans are generally issued sequentially and the net proceeds of the latest debt is used by the borrower to pay off the preceding loan. A construction loan ( in the form of a promissory note) is generally expected to be paid off with the net proceeds from permanent financing.

+ References+ Details

- Definition

Reflects the sum of the gross carrying amounts of unpaid loans issued to businesses to acquire, develop, construct, improve, or refinance land or a building. Includes [but is not limited to] commercial mortgage loans, which are secured by a [legal] security interest in real property [commercial building or business real property] which thereby serves as collateral securing repayment of the loan; and construction financing, which is an obligation generally in the form of a [promissory] note, used for the funding of construction projects.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-Publisher AICPA

-Name Statement of Position (SOP)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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+ Details