Loans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Loans [Line Items]
Deferred discounts, finance charges and Interest Included in receivables	$ 2,600	$ (9,200)
Federal Home Loan Bank advances	153,831	853,431
Accretion to interest income	23,218	24,115
Federal Agency Borrowings
Loans [Line Items]
Loans pledged as collateral	6,700,000	3,800,000
Federal Home Loan Bank Advances
Loans [Line Items]
Loans pledged as collateral	6,100,000
Federal Reserve Bank Advances
Loans [Line Items]
Loans pledged as collateral	630,700
Premium finance receivables
Loans [Line Items]
Loans and leases receivable, deferred income	$ 69,600	$ 56,700

Amount of accretion recognized for 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
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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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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

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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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Deferred Discounts, Finance Charges and Interest and Other Adjustments Included in Receivables

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Loans [Line Items]

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