Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financial assets
Cash and due from banks	$ 374,921	$ 444,113
Cash and due from banks, Fair Value	374,921	444,113
Interest-bearing deposits in other financial institutions	79,764	571,924
Interest-bearing deposits in other financial institutions, fair value	79,764	571,924
Federal funds sold and securities purchased under agreements to resell	19,000	16,030
Federal funds sold and securities purchased under agreements to resell, fair value	19,000	16,030
Investment securities held to maturity	1,168,230	404,455
Investment securities held to maturity, fair value	1,184,442	413,067
Investment securities available for sale	4,967,414	5,396,812
Investment securities available for sale, at fair value	4,967,414	5,396,812
FHLB and Federal Reserve Bank stocks	147,240	189,107
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	147,240	189,107
Loans held for sale	124,915	154,935
Loans held for sale, fair value	124,915	156,423
Loans, net	18,440,079	17,327,544
Loans, net, fair value	18,389,832	17,427,647
Bank owned life insurance	583,019	574,154
Bank owned life insurance, fair value	583,019	574,154
Interest rate-related instruments	29,391	33,023
Interest rate-related agreements, fair value	29,391	33,023
Foreign currency exchange forwards	1,532	2,140
Foreign currency exchange forwards, fair value	1,532	2,140
Forward commitments to sell residential mortgage loans	958	1,947
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	958	1,947
Purchased options (time deposit)	2,715	6,054
Purchased options (time deposit), fair value	2,715	6,054
Commodity contracts	1,269
Commodity contracts, fair value	1,269
Forward Commitments, assets	403
Forward Commitments Fair Value Disclosure Assets	403
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	19,444,863	17,192,049
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	19,444,863	17,192,049
Brokered CDs and other time deposits	1,562,802	1,571,455
Brokered CDs and other time deposits, fair value	1,564,464	1,571,455
Short-term funding	834,416	1,068,288
Short-term funding, fair value	834,416	1,068,288
Long-term funding	2,679,350	3,930,117
Long-term funding, fair value	2,728,112	3,975,605
Interest rate-related instruments	30,886	35,372
Interest rate-related agreements, fair value	30,886	35,372
Foreign currency exchange forwards	1,398	1,957
Foreign currency exchange forwards, fair value	1,398	1,957
Standby letters of credit	2,954	3,542
Standby letters of credit, fair value	2,954	3,542
Forward commitments to sell residential mortgage loans		2,435
Forward commitments to sell residential mortgage loans, fair value		2,435
Written options (time deposit)	2,715	6,054
Written options (time deposit), fair value	2,715	6,054
Commodity Contract Liability	1,146
Commodity Contract Liability, Fair Value	1,146
Fair Value, Inputs, Level 1 [Member]
Financial assets
Cash and due from banks, Fair Value	374,921	444,113
Interest-bearing deposits in other financial institutions, fair value	79,764	571,924
Federal funds sold and securities purchased under agreements to resell, fair value	19,000	16,030
Investment securities held to maturity, fair value	0	0
Investment securities available for sale, at fair value	2,566	3,957
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	0	0
Loans held for sale, fair value	0	0
Loans, net, fair value	0	0
Bank owned life insurance, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	0	0
Purchased options (time deposit), fair value	0	0
Commodity contracts, fair value	0
Forward Commitments Fair Value Disclosure Assets	0
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	0	0
Brokered CDs and other time deposits, fair value	0	0
Short-term funding, fair value	0	0
Long-term funding, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Standby letters of credit, fair value	0	$ 0
Forward commitments to sell residential mortgage loans, fair value
Written options (time deposit), fair value	0	$ 0
Commodity Contract Liability, Fair Value	0
Fair Value, Inputs, Level 2 [Member]
Financial assets
Cash and due from banks, Fair Value	0	0
Interest-bearing deposits in other financial institutions, fair value	0	0
Federal funds sold and securities purchased under agreements to resell, fair value	0	0
Investment securities held to maturity, fair value	1,184,442	413,067
Investment securities available for sale, at fair value	4,964,648	5,392,655
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	147,240	189,107
Loans held for sale, fair value	124,915	156,423
Loans, net, fair value	0	0
Bank owned life insurance, fair value	583,019	574,154
Interest rate-related agreements, fair value	29,391	33,023
Foreign currency exchange forwards, fair value	1,532	2,140
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	0	0
Purchased options (time deposit), fair value	2,715	6,054
Commodity contracts, fair value	1,269
Forward Commitments Fair Value Disclosure Assets	0
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	0	0
Brokered CDs and other time deposits, fair value	1,564,464	1,571,455
Short-term funding, fair value	834,416	1,068,288
Long-term funding, fair value	2,728,112	3,975,605
Interest rate-related agreements, fair value	30,886	35,372
Foreign currency exchange forwards, fair value	1,398	1,957
Standby letters of credit, fair value	2,954	3,542
Forward commitments to sell residential mortgage loans, fair value		0
Written options (time deposit), fair value	2,715	6,054
Commodity Contract Liability, Fair Value	1,146
Fair Value, Inputs, Level 3 [Member]
Financial assets
Cash and due from banks, Fair Value	0	0
Interest-bearing deposits in other financial institutions, fair value	0	0
Federal funds sold and securities purchased under agreements to resell, fair value	0	0
Investment securities held to maturity, fair value	0	0
Investment securities available for sale, at fair value	200	200
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	0	0
Loans held for sale, fair value	0	0
Loans, net, fair value	18,389,832	17,427,647
Bank owned life insurance, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	958	1,947
Purchased options (time deposit), fair value	0	0
Commodity contracts, fair value	0
Forward Commitments Fair Value Disclosure Assets	403
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	19,444,863	17,192,049
Brokered CDs and other time deposits, fair value	0	0
Short-term funding, fair value	0	0
Long-term funding, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Standby letters of credit, fair value	0	0
Forward commitments to sell residential mortgage loans, fair value		2,435
Written options (time deposit), fair value	0	$ 0
Commodity Contract Liability, Fair Value	$ 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.