Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025	Dec. 31, 2024
Assets, Fair Value Disclosure [Abstract]
Cash and Due from Banks	$ 548,057	$ 574,698
Interest-bearing Deposits in Banks and Other Financial Institutions	1,268,379	1,144,123
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	14,355	1,400
Debt Securities, Available-for-Sale	6,366,586	5,397,563
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,510,775	3,602,576
Debt Securities, Held-to-Maturity, Fair Value	3,091,818	3,190,994
Equity Securities, FV-NI and without Readily Determinable Fair Value	29,960	26,060
FHLB and Federal Reserve Bank stocks	329,436	252,514
Loans and Leases Receivable, Net Amount	36,023,311	30,785,546
Life Insurance, Corporate or Bank Owned, Amount	717,116	694,452
Assets	51,812,506	45,202,596
Liabilities, Fair Value Disclosure
Noninterest-bearing Domestic Deposit, Demand	6,908,338	6,126,632
Deposits	39,931,255	35,552,608
Federal Funds Purchased and Securities Sold under Agreements to Repurchase	529,276	307,864
Short-Term Debt	529,276	307,864
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	4,574,681	3,268,094
Other Long-Term Debt	591,080	594,276
Liabilities	46,174,383	40,227,249
Standby Letters of Credit [Member]
Liabilities, Fair Value Disclosure
Lending Related Commitments	252,800	222,000
Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	21,339	19,286
Liabilities, Fair Value Disclosure
Derivative Liability	5,046	1,833
Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Cash and Due from Banks	548,057	574,698
Interest-bearing Deposits in Banks and Other Financial Institutions	1,268,379	1,144,123
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	14,355	1,400
Equity Securities, FV-NI	14,960	11,060
Equity Securities, FV-NI and without Readily Determinable Fair Value	29,960	26,060
FHLB and Federal Reserve Bank stocks	329,436	252,514
Loan, Mortgage, Held-for-Sale, Fair Value Disclosure	94,490	72,499
Loan, Held-for-Sale, Fair Value Disclosure	15,000
Loans and Leases Receivable, Net Amount	35,976,291	30,766,886
Loans Receivable, Fair Value Disclosure	35,021,793	29,970,788
Life Insurance, Corporate or Bank Owned, Amount	717,116	694,452
Servicing Asset	87,683	86,337
Assets	49,024,483	42,699,714
Assets, Fair Value Disclosure	47,651,028	41,492,034
Liabilities, Fair Value Disclosure
Brokered CDs, Carrying Amount	3,933,787	3,795,133
Brokered CDs, Fair Value	3,923,505	3,791,245
Time Deposits, at Carrying Value	4,782,343	4,041,178
Time Deposits	4,771,175	4,035,549
Federal Funds Purchased and Securities Sold under Agreements to Repurchase	529,276	307,864
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	529,276	307,864
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	4,574,681	3,268,094
Federal Home Loan Bank Borrowings, Fair Value Disclosure	4,568,111	3,267,836
Other Long-Term Debt	591,080	594,276
Long-term Debt, Fair Value	589,506	598,141
Long-Term Line of Credit	2,365	2,225
Liabilities	14,532,613	12,119,557
Liabilities, Fair Value Disclosure	14,503,019	12,113,647
Fair Value, Measurements, Recurring | Interest Rate Lock Commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	1,432	814
Fair Value, Measurements, Recurring | Commitments [Member]
Liabilities, Fair Value Disclosure
Derivative Liability	397	444
Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	1,435	10,517
Liabilities, Fair Value Disclosure
Derivative Liability	6,737	1
Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	1,355	757
Liabilities, Fair Value Disclosure
Foreign Currency Contracts, Liability, Fair Value Disclosure	303	194
Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	61,693	66,787
Liabilities, Fair Value Disclosure
Derivative Liability	111,446	108,631
Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	440	1,731
Liabilities, Fair Value Disclosure
Foreign Currency Contracts, Liability, Fair Value Disclosure	198	1,517
US Treasury Securities
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	997	996
Debt Securities, Held-to-Maturity, Fair Value	1,002	1,015
US Treasury Securities | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	997	996
Debt Securities, Held-to-Maturity, Fair Value	1,002	1,015
US States and Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	7,240	3,044
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,591,681	1,628,088
Debt Securities, Held-to-Maturity, Fair Value	1,468,604	1,507,302
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	7,240	3,044
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,591,681	1,628,088
Debt Securities, Held-to-Maturity, Fair Value	1,468,604	1,507,302
Residential Mortgage-Backed Securities [Member] | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	137,288	129,863
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	790,729	823,630
Debt Securities, Held-to-Maturity, Fair Value	660,737	696,462
Residential Mortgage-Backed Securities [Member] | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	5,491,648	5,039,829
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	37,215	39,123
Debt Securities, Held-to-Maturity, Fair Value	34,626	36,884
Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	137,288	129,863
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	790,729	823,630
Debt Securities, Held-to-Maturity, Fair Value	660,737	696,462
Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	5,491,648	5,039,829
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	37,215	39,123
Debt Securities, Held-to-Maturity, Fair Value	34,626	36,884
Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	292,007	302,817
Debt Securities, Held-to-Maturity, Fair Value	246,460	258,827
Commercial Mortgage-Backed Securities [Member] | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	410,221	16,958
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	757,723	763,370
Debt Securities, Held-to-Maturity, Fair Value	644,300	650,366
Commercial Mortgage-Backed Securities [Member] | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	106,844	109,556
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	40,423	44,552
Debt Securities, Held-to-Maturity, Fair Value	36,089	40,138
Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	410,221	16,958
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	757,723	763,370
Debt Securities, Held-to-Maturity, Fair Value	644,300	650,366
Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	106,844	109,556
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	40,423	44,552
Debt Securities, Held-to-Maturity, Fair Value	36,089	40,138
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	88,212	95,046
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Fair Value	0
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	88,212	95,046
US Government-sponsored Enterprises Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	120,070	269
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Fair Value	0
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	120,070	269
Other Debt Obligations | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	5,063	2,998
Available-for-sale Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	6,366,586	5,397,563
Held-to-maturity Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,510,775	3,602,576
Debt Securities, Held-to-Maturity, Fair Value	3,091,818	3,190,994
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Cash and Due from Banks	548,057	574,698
Interest-bearing Deposits in Banks and Other Financial Institutions	1,268,379	1,144,123
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	14,355	1,400
Equity Securities, FV-NI	14,960	11,060
FHLB and Federal Reserve Bank stocks	0	0
Loan, Mortgage, Held-for-Sale, Fair Value Disclosure	0	0
Loan, Held-for-Sale, Fair Value Disclosure	0
Loans Receivable, Fair Value Disclosure	0	0
Life Insurance, Corporate or Bank Owned, Amount	0	0
Servicing Asset	0	0
Assets, Fair Value Disclosure	1,846,753	1,732,296
Liabilities, Fair Value Disclosure
Brokered CDs, Fair Value	0	0
Time Deposits	0	0
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	529,276	307,864
Federal Home Loan Bank Borrowings, Fair Value Disclosure	0	0
Long-term Debt, Fair Value	0	0
Long-Term Line of Credit	0	0
Liabilities, Fair Value Disclosure	529,276	307,864
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Interest Rate Lock Commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Commitments [Member]
Liabilities, Fair Value Disclosure
Derivative Liability	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	0	0
Liabilities, Fair Value Disclosure
Derivative Liability	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	0	0
Liabilities, Fair Value Disclosure
Derivative Liability	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 | US Treasury Securities | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	1,002	1,015
Fair Value, Inputs, Level 1 | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 1 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 1 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 1 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 1 | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 1 | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 1 | Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Fair Value, Inputs, Level 1 | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Fair Value, Inputs, Level 1 | Other Debt Obligations | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Fair Value, Inputs, Level 1 | Available-for-sale Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Fair Value, Inputs, Level 1 | Held-to-maturity Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	1,002	1,015
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Cash and Due from Banks	0	0
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	0	0
Equity Securities, FV-NI	0	0
FHLB and Federal Reserve Bank stocks	329,436	252,514
Loan, Mortgage, Held-for-Sale, Fair Value Disclosure	94,490	72,499
Loan, Held-for-Sale, Fair Value Disclosure	15,000
Loans Receivable, Fair Value Disclosure	0	0
Life Insurance, Corporate or Bank Owned, Amount	717,116	694,452
Servicing Asset	0	0
Assets, Fair Value Disclosure	10,676,304	9,686,799
Liabilities, Fair Value Disclosure
Brokered CDs, Fair Value	3,923,505	3,791,245
Time Deposits	4,771,175	4,035,549
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure	4,568,111	3,267,836
Long-term Debt, Fair Value	589,506	598,141
Long-Term Line of Credit	2,365	2,225
Liabilities, Fair Value Disclosure	13,973,346	11,805,339
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	440	1,731
Liabilities, Fair Value Disclosure
Derivative Liability	198	1,517
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Interest Rate Lock Commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	0	0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Commitments [Member]
Liabilities, Fair Value Disclosure
Derivative Liability	0	0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	1,435	10,517
Liabilities, Fair Value Disclosure
Derivative Liability	6,737	1
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	1,355	757
Foreign Currency Contract, Asset, Fair Value Disclosure	1,355	757
Liabilities, Fair Value Disclosure
Derivative Liability	303	194
Foreign Currency Contracts, Liability, Fair Value Disclosure	303	194
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	61,693	66,787
Liabilities, Fair Value Disclosure
Derivative Liability	111,446	108,631
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	440	1,731
Liabilities, Fair Value Disclosure
Foreign Currency Contracts, Liability, Fair Value Disclosure	198	1,517
Fair Value, Inputs, Level 2 | US Treasury Securities | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 2 | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	7,240	3,044
Debt Securities, Held-to-Maturity, Fair Value	1,468,604	1,507,302
Fair Value, Inputs, Level 2 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	137,288	129,863
Debt Securities, Held-to-Maturity, Fair Value	660,737	696,462
Fair Value, Inputs, Level 2 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	5,491,648	5,039,829
Debt Securities, Held-to-Maturity, Fair Value	34,626	36,884
Fair Value, Inputs, Level 2 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	246,460	258,827
Fair Value, Inputs, Level 2 | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	410,221	16,958
Debt Securities, Held-to-Maturity, Fair Value	644,300	650,366
Fair Value, Inputs, Level 2 | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	106,844	109,556
Debt Securities, Held-to-Maturity, Fair Value	36,089	40,138
Fair Value, Inputs, Level 2 | Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	88,212	95,046
Fair Value, Inputs, Level 2 | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	120,070	269
Fair Value, Inputs, Level 2 | Other Debt Obligations | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	3,000	2,998
Fair Value, Inputs, Level 2 | Available-for-sale Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	6,364,523	5,397,563
Fair Value, Inputs, Level 2 | Held-to-maturity Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	3,090,816	3,189,979
Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	2,100
Equity Securities, FV-NI		0	$ 72
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Cash and Due from Banks	0	0
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	0	0
Equity Securities, FV-NI	0	0
FHLB and Federal Reserve Bank stocks	0	0
Loan, Mortgage, Held-for-Sale, Fair Value Disclosure	0	0
Loan, Held-for-Sale, Fair Value Disclosure	0
Loans Receivable, Fair Value Disclosure	35,021,793	29,970,788
Life Insurance, Corporate or Bank Owned, Amount	0	0
Servicing Asset	87,683	86,337
Assets, Fair Value Disclosure	35,112,971	30,057,939
Liabilities, Fair Value Disclosure
Brokered CDs, Fair Value	0	0
Time Deposits	0	0
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure	0	0
Long-term Debt, Fair Value	0	0
Long-Term Line of Credit	0	0
Liabilities, Fair Value Disclosure	397	444
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Interest Rate Lock Commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	1,432	814
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Commitments [Member]
Liabilities, Fair Value Disclosure
Derivative Liability	397	444
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	0	0
Liabilities, Fair Value Disclosure
Derivative Liability	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Designated as Hedging Instrument | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Interest Rate Contract
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	0	0
Liabilities, Fair Value Disclosure
Derivative Liability	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument [Member] | Interest Rate Lock Commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Asset	1,432	814
Fair Value, Inputs, Level 3 | US Treasury Securities | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 3 | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 3 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 3 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 3 | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 3 | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | US Government Sponsored-Enterprise Insured Loans
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 3 | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, Level 3 | Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Fair Value, Inputs, Level 3 | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	0	0
Fair Value, Inputs, Level 3 | Other Debt Obligations | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	2,063	0
Fair Value, Inputs, Level 3 | Available-for-sale Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Available-for-Sale	2,063	0
Fair Value, Inputs, Level 3 | Held-to-maturity Securities [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-Maturity, Fair Value	0	0
Fair Value, Inputs, NAV [Member] | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Equity Securities, FV-NI	$ 15,000	$ 15,000