Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financial assets
Cash and due from banks	$ 328,260	$ 483,666
Interest-bearing deposits in other financial institutions	94,918	199,702
Federal funds sold and securities purchased under agreements to resell	10,000	32,650
Investment securities held to maturity	2,443,203	2,282,853
Investment securities held to maturity, fair value	2,407,197	2,283,574
Investment securities available for sale	4,485,875	4,043,446
FHLB and Federal Reserve Bank stocks	233,216	165,331
Commercial Loans Held-for-sale, Fair Value Disclosure	6,091	0
Loans, net	22,553,433	20,519,111
Bank and Corporate Owned Life Insurance	657,841	591,057
Derivatives (trading and other assets)	102,890	69,675
Financial liabilities
Short-term funding	2,146,374	676,282
Long-term funding	3,233,338	3,397,450
Derivatives (trading and other liabilities)	100,247	67,660
Letters of Credit Outstanding, Amount	254,000	235,000
Fair Value, Inputs, Level 1
Financial assets
Cash and due from banks	328,260	483,666
Cash and due from banks, Fair Value	328,260	483,666
Interest-bearing deposits in other financial institutions	94,918	199,702
Interest-bearing deposits in other financial institutions, fair value	94,918	199,702
Federal funds sold and securities purchased under agreements to resell	10,000	32,650
Federal funds sold and securities purchased under agreements to resell, fair value	10,000	32,650
Investment securities available for sale	2,594	2,628
Investment securities available for sale, fair value	2,594	2,628
Fair Value, Inputs, Level 2
Financial assets
Investment securities held to maturity	2,443,203	2,282,853
Investment securities held to maturity, fair value	2,407,197	2,283,574
Investment securities available for sale	4,483,281	4,040,818
Investment securities available for sale, fair value	4,483,281	4,040,818
FHLB and Federal Reserve Bank stocks	233,216	165,331
FHLB and Federal Reserve Bank stocks, fair value	233,216	165,331
Commercial loans held for sale	6,091	0
Commercial Loans Held-for-sale, Fair Value Disclosure	6,091	0
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	103,953	85,544
Residential Held-for-sale, Fair Value Disclosure	103,953	85,544
Bank and Corporate Owned Life Insurance	657,841	591,057
Bank owned life insurance, fair value	657,841	591,057
Derivatives (trading and other assets)	104,099	70,850
Derivatives (trading and other assets), fair value	104,099	70,850
Financial liabilities
Brokered CDs and other time deposits	2,677,372	2,349,069
Brokered CDs and other time deposits, fair value	2,677,372	2,349,069
Short-term funding	2,146,374	676,282
Short-term funding, fair value	2,146,374	676,282
Long-term funding	3,233,338	3,397,450
Long-term funding, fair value	3,242,517	3,411,368
Standby letters of credit	2,468	2,402
Standby letters of credit, fair value	2,468	2,402
Derivatives (trading and other liabilities)	101,198	68,835
Derivatives (trading and other liabilities), fair value	101,198	68,835
Fair Value, Inputs, Level 3
Financial assets
Loans, net	22,553,433	20,519,111
Loans, net, fair value	22,195,415	20,314,984
Derivatives (trading and other assets)	3,032	1,538
Derivatives (trading and other assets), fair value	3,032	1,538
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	21,148,230	20,436,893
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	21,148,230	20,436,893
Derivatives (trading and other liabilities)	303	313
Derivatives (trading and other liabilities), fair value	$ 303	$ 313

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.