Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial assets
Cash and due from banks	$ 483,666	$ 446,558
Interest-bearing deposits in other financial institutions	199,702	149,175
Federal funds sold and securities purchased under agreements to resell	32,650	46,500
Investment securities held to maturity	2,282,853	1,273,536
Investment securities held to maturity, fair value	2,283,574	1,264,674
Investment securities available for sale	4,043,446	4,680,226
FHLB and Federal Reserve Bank stocks	165,331	140,001
Commercial loans held for sale	0	12,474
Loans, net	20,519,111	19,776,381
Bank and Corporate Owned Life Insurance	591,057	585,290
Trading Assets	69,675	52,398
Financial liabilities
Short-term funding	676,282	1,092,035
Long-term funding	3,397,450	2,761,795
Derivatives (trading and other liabilities)	67,660	51,103
Commitment on standby letters of credit	235,000	260,000
Fair Value, Inputs, Level 1
Financial assets
Cash and due from banks	483,666	446,558
Cash and due from banks, Fair Value	483,666	446,558
Interest-bearing deposits in other financial institutions	199,702	149,175
Interest-bearing deposits in other financial institutions, fair value	199,702	149,175
Federal funds sold and securities purchased under agreements to resell	32,650	46,500
Federal funds sold and securities purchased under agreements to resell, fair value	32,650	46,500
Investment securities available for sale	2,628	2,602
Investment securities available for sale, at fair value	2,628	2,602
Fair Value, Inputs, Level 2
Financial assets
Investment securities held to maturity	2,282,853	1,273,536
Investment securities held to maturity, fair value	2,283,574	1,264,674
Investment securities available for sale	4,040,818	4,677,424
Investment securities available for sale, at fair value	4,040,818	4,677,424
FHLB and Federal Reserve Bank stocks	165,331	140,001
FHLB and Federal Reserve Bank stocks, fair value	165,331	140,001
Commercial loans held for sale	0	12,474
Commercial Loans Held-for-sale, Fair Value Disclosure	0	12,474
Mortgage Loans Held-for-sale	85,544	108,010
Mortgages Held-for-sale, Fair Value Disclosure	85,544	108,010
Bank and Corporate Owned Life Insurance	591,057	585,290
Bank owned life insurance, fair value	591,057	585,290
Trading Assets	70,850	54,974
Derivatives (trading and other assets), fair value	70,850	54,974
Financial liabilities
Brokered CDs and other time deposits	2,349,069	1,606,127
Brokered CDs and other time deposits, fair value	2,349,069	1,606,127
Short-term funding	676,282	1,092,035
Short-term funding, fair value	676,282	1,092,035
Long-term funding	3,397,450	2,761,795
Long-term funding, fair value	3,411,368	2,791,841
Standby letters of credit	2,402	2,566
Standby letters of credit, fair value	2,402	2,566
Derivatives (trading and other liabilities)	68,835	53,679
Derivatives (trading and other liabilities), fair value	68,835	53,679
Fair Value, Inputs, Level 3
Financial assets
Investment securities available for sale	0	200
Investment securities available for sale, at fair value	0	200
Loans, net	20,519,111	19,776,381
Loans, net, fair value	20,314,984	19,680,317
Trading Assets	1,538	3,114
Derivatives (trading and other assets), fair value	1,538	3,114
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	20,436,893	20,282,321
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts, fair value	20,436,893	20,282,321
Derivatives (trading and other liabilities)	313	0
Derivatives (trading and other liabilities), fair value	$ 313	$ 0

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.