Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial assets
Cash and due from banks	$ 334,138	$ 343,831
Interest-bearing deposits in other financial institutions	166,929	681,684
Available-for-sale Securities		4,332,015
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,939,920	2,239,003
Investment securities held to maturity, fair value	3,764,901	2,348,664
Equity securities with readily determinable fair values, Fair Value	5,000	5,000
Equity Securities without Readily Determinable Fair Value, Amount	14,000	14,000
Investment securities gains (losses), net	18,560	18,352
FHLB and Federal Reserve Bank stocks	168,281	168,281
Residential loans held for sale	91,582	136,638
Loans, net	24,252,867	23,944,934
Bank owned life insurance, fair value	679,538	680,021
Servicing Asset at Fair Value, Amount	67,015	57,158
Financial liabilities
Short-term funding	399,361	354,262
Other long-term funding	249,797	249,324
FHLB advances	1,537,948	1,621,047
Letters of Credit Outstanding, Amount	257,000	248,000
US Treasury Securities
Financial assets
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	998	1,000
Investment securities held to maturity, fair value	964	1,001
Fair Value, Inputs, Level 1
Financial assets
Available-for-sale Securities	116,132	122,957
Equity securities with readily determinable fair value, Carrying Amount	5,025	4,810
Equity securities with readily determinable fair values, Fair Value	5,025	4,810
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | US Treasury Securities
Financial assets
Available-for-sale Securities	116,132	122,957
Fair Value, Inputs, Level 2
Financial assets
Available-for-sale Securities	2,664,671	4,209,058
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,938,857	2,237,947
Investment securities held to maturity, fair value	3,763,872	2,347,608
Financial liabilities
Brokered CDs and other time deposits	1,288,913	1,347,262
Brokered CDs and other time deposits, fair value	1,288,913	1,347,262
Short-term funding	399,361	354,262
Short-term funding, fair value	399,270	354,248
Long-term funding, fair value	254,355	265,545
Advances, Fair Value Disclosure	1,546,821	1,680,814
Other long-term funding	249,797	249,324
Standby letters of credit	2,473	2,367
Standby letters of credit, fair value	2,473	2,367
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | US Treasury Securities
Financial assets
Available-for-sale Securities		122,957
Fair Value, Inputs, Level 2 | Other Assets [Member]
Financial assets
Derivative Asset	33,715	90,379
Derivatives (trading and other assets), fair value	33,715	90,379
Fair Value, Inputs, Level 2 | Other Liabilities [Member]
Financial liabilities
Derivatives (trading liabilities)	113,844	32,921
Derivatives (trading and other liabilities), fair value	113,844	32,921
Fair Value, Inputs, Level 3
Financial assets
Equity Securities without Readily Determinable Fair Value, Amount	13,535	13,542
Investment securities gains (losses), net	13,535	13,542
Loans, net, fair value	23,485,798	23,980,330
Servicing Asset at Fair Value, Amount	67,015	57,259
Servicing Asset	67,015	54,862
Derivative Asset	4,796	30
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	27,116,495	27,119,167
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	27,116,495	27,119,167
Derivatives (trading liabilities)	234	0
Fair Value, Inputs, Level 3 | Mortgage banking(a)(b) | Fair Value, Measurements, Recurring
Financial assets
Derivative Asset	0	2,617
Financial liabilities
Derivatives (trading liabilities)	224	0
Fair Value, Inputs, Level 3 | Interest Rate Lock Commitments and Forward Commitments Total | Fair Value, Measurements, Recurring
Financial assets
Derivative Asset	4,796	2,647
Fair Value, Inputs, Level 3 | Forward commitments (mortgage)
Financial assets
Derivative Asset	4,796	30
Financial liabilities
Derivatives (trading liabilities)	9	0
Derivatives (trading and other liabilities), fair value	$ 9	$ 0