Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Financial assets
Cash and due from banks	$ 401,151	$ 373,380
Interest-bearing deposits in other financial institutions	712,416	207,624
Federal funds sold and securities purchased under agreements to resell	95	7,740
Investment securities held to maturity, net	1,990,940	2,205,083
Investment securities held to maturity, fair value	2,124,452	2,276,465
Investment securities available for sale	3,258,360	3,262,586
Investment securities available for sale, fair value			$ 692,000
Equity securities with readily determinable fair values, Fair Value	2,000	2,000
Equity Securities without Readily Determinable Fair Value, Amount	13,000	13,000
Investment securities gains (losses), net	15,090	15,090
FHLB and Federal Reserve Bank stocks	168,280	227,347
Loans, net	24,619,041	22,620,068
Financial liabilities
Short-term funding	206,316	465,113
Other long-term funding	1,571,418	549,343
PPPLF	1,022,217	0
FHLB advances	1,706,763	3,180,967
Letters of Credit Outstanding, Amount	252,000	278,000
Fair Value, Inputs, Level 1
Financial assets
Cash and due from banks	401,151	373,380
Cash and due from banks, Fair Value	401,151	373,380
Interest-bearing deposits in other financial institutions	712,416	207,624
Interest-bearing deposits in other financial institutions, fair value	712,416	207,624
Federal funds sold and securities purchased under agreements to resell	95	7,740
Federal funds sold and securities purchased under agreements to resell, fair value	95	7,740
Investment securities held to maturity, net	999	999
Investment securities held to maturity, fair value	1,030	1,018
Investment securities available for sale	26,650	0
Investment securities available for sale, fair value	26,650	0
Equity securities with readily determinable fair value, Carrying Amount	1,646	1,646
Equity securities with readily determinable fair values, Fair Value	1,646	1,646
Fair Value, Inputs, Level 2
Financial assets
Investment securities held to maturity, net	1,989,870	2,204,084
Investment securities held to maturity, fair value	2,123,351	2,275,447
Investment securities available for sale	3,231,711	3,262,586
Investment securities available for sale, fair value	3,231,711	3,262,586
FHLB and Federal Reserve Bank stocks	168,280	227,347
FHLB and Federal Reserve Bank stocks, fair value	168,280	227,347
Residential Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	130,139	136,280
Residential Held-for-sale, Fair Value Disclosure	130,139	136,280
Commercial loans held for sale	19,360	15,000
Commercial Loans Held-for-sale, Fair Value Disclosure	19,360	15,000
Bank and Corporate Owned Life Insurance	679,257	671,948
Bank owned life insurance, fair value	679,257	671,948
Financial liabilities
Brokered CDs and other time deposits	2,026,852	2,622,803
Brokered CDs and other time deposits, fair value	2,039,995	2,622,803
Short-term funding	206,316	465,113
Short-term funding, fair value	206,316	465,113
Other long-term funding	549,201	549,343
Long-term funding, fair value	589,717	572,873
PPPLF	1,022,217	0
Paycheck Protection Program Loan Funding Fair Value	1,022,399	0
FHLB advances	1,706,763	3,180,967
Advances, Fair Value Disclosure	1,851,567	3,207,793
Standby letters of credit	2,489	2,710
Standby letters of credit, fair value	2,489	2,710
Fair Value, Inputs, Level 2 \| Other Assets [Member]
Financial assets
Derivative Asset	256,557	101,778
Derivatives (trading and other assets), fair value	256,557	101,778
Fair Value, Inputs, Level 2 \| Other Liabilities [Member]
Financial liabilities
Derivatives (trading liabilities)	57,999	36,745
Derivatives (trading and other liabilities), fair value	57,999	36,745
Fair Value, Inputs, Level 3
Financial assets
Equity Securities without Readily Determinable Fair Value, Amount	13,444	13,444
Investment securities gains (losses), net	13,444	13,444
Loans, net	24,619,041	22,620,068
Loans, net, fair value	24,532,881	22,399,621
Derivative Asset	7,888	2,527
Derivatives (trading and other assets), fair value	7,888	2,527
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	24,685,695	21,156,261
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	24,685,695	21,156,261
Derivatives (trading liabilities)	0	710
Derivatives (trading and other liabilities), fair value	$ 0	$ 710

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.