Loans (Narrative) (Details) - USD ($)	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Loans [Line Items]
Deferred discounts, finance charges and Interest Included in receivables	$ (9,200,000)	$ 330,000
Loans pledged as collateral	3,800,000,000	3,600,000,000
Federal Home Loan Bank advances	859,876,000	733,050,000
Accretion to interest income	24,115,000	36,956,000
Federal Home Loan Bank Advances
Loans [Line Items]
Loans pledged as collateral	3,200,000,000
Federal Reserve Bank Advances
Loans [Line Items]
Loans pledged as collateral	579,200,000
Premium finance receivables
Loans [Line Items]
Loans and leases receivable, deferred income	$ 56,700,000	$ 46,900,000

Amount of decrease from accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

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-Publisher FASB
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Unearned discounts (other than cash or quantity discounts and the like), finance charges, and interest included in the face amount of receivables, that are shown as a deduction from the related receivables. For example, 1) finance charges booked as a receivable when a loan is made and recognized as income at a later date; and 2) interest charges deducted from the face loan amount, resulting in a discounted amount actually advanced to the borrower (wherein the receivable includes the amount actually advanced to the borrower and the as yet unearned interest income).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 470
-Section 50
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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 20
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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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- Definition

Loans [Line Items]

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