Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financial assets
Cash and due from banks	$ 354,331	$ 446,558
Interest-bearing deposits in other financial institutions	109,596	149,175
Federal funds sold and securities purchased under agreements to resell	27,700	46,500
Investment securities held to maturity	2,233,579	1,273,536
Investment securities held to maturity, fair value	2,243,845	1,264,674
Investment securities available for sale	3,801,699	4,680,226
FHLB and Federal Reserve Bank stocks	172,446	140,001
Commercial loans held for sale	9,718	12,474
Loans, net	20,654,909	19,776,381
Derivatives (trading and other assets)	48,429	52,398
Financial liabilities
Short-term funding	1,064,617	1,092,035
Long-term funding	3,147,285	2,761,795
Derivatives (trading and other liabilities)	46,812	51,103
Letters of Credit Outstanding, Amount	234,000	260,000
Fair Value, Inputs, Level 1
Financial assets
Cash and due from banks	354,331	446,558
Cash and due from banks, Fair Value	354,331	446,558
Interest-bearing deposits in other financial institutions	109,596	149,175
Interest-bearing deposits in other financial institutions, fair value	109,596	149,175
Federal funds sold and securities purchased under agreements to resell	27,700	46,500
Federal funds sold and securities purchased under agreements to resell, fair value	27,700	46,500
Investment securities available for sale	2,651	2,602
Investment securities available for sale, fair value	2,651	2,602
Fair Value, Inputs, Level 2
Financial assets
Investment securities held to maturity	2,233,579	1,273,536
Investment securities held to maturity, fair value	2,243,845	1,264,674
Investment securities available for sale	3,799,048	4,677,424
Investment securities available for sale, fair value	3,799,048	4,677,424
FHLB and Federal Reserve Bank stocks	172,446	140,001
FHLB and Federal Reserve Bank stocks, fair value	172,446	140,001
Commercial loans held for sale	9,718	12,474
Commercial Loans Held-for-sale, Fair Value Disclosure	9,718	12,474
Residential Loans on Real Estate, Carrying Amount of Mortgages	113,064	108,010
Residential Held-for-sale, Fair Value Disclosure	113,064	108,010
Bank owned life insurance	589,093	585,290
Bank owned life insurance, fair value	589,093	585,290
Derivatives (trading and other assets)	49,863	54,974
Derivatives (trading and other assets), fair value	49,863	54,974
Financial liabilities
Brokered CDs and other time deposits	2,321,277	1,606,127
Brokered CDs and other time deposits, fair value	2,321,277	1,606,127
Short-term funding	1,064,617	1,092,035
Short-term funding, fair value	1,064,617	1,092,035
Long-term funding	3,147,285	2,761,795
Long-term funding, fair value	3,171,059	2,791,841
Standby letters of credit	2,346	2,566
Standby letters of credit, fair value	2,346	2,566
Derivatives (trading and other liabilities)	48,246	53,679
Derivatives (trading and other liabilities), fair value	48,246	53,679
Fair Value, Inputs, Level 3
Financial assets
Investment securities available for sale	0	200
Investment securities available for sale, fair value	0	200
Loans, net	20,654,909	19,776,381
Loans, net, fair value	20,504,971	19,680,317
Derivatives (trading and other assets)	2,963	3,114
Derivatives (trading and other assets), fair value	2,963	3,114
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	20,012,174	20,282,321
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	$ 20,012,174	$ 20,282,321

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

No definition available.