Borrowings - FHLB and FRB Advances (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
FHLB advances	$ 1,540,000
Amount
2024	250,000
2025	200,000
2026	540,000
2027	450,000
Thereafter	100,000
FHLB advances	$ 1,540,000
Rate
2024	3.44%
2025	4.45%
2026	5.54%
2027	3.70%
Thereafter	4.19%
Total maximum borrowing capacity with the FHLB	$ 3,393,013	$ 3,241,120
Total maximum borrowing capacity with the FRB	5,013,377	2,510,189
Loans and leases receivable	12,463,485	13,144,894
Qualifying Assets Pledged As Collateral
Rate
Loans and leases receivable	10,050,340	7,142,865
FHLB advances
Debt Instrument [Line Items]
Total long-term debt	$ 1,529,839	$ 500,000
FHLB advances, rate	4.43%	3.37%
Unamortized basis adjustments from interest rate swaps designated as fair value hedges of long-term advances from FHLB	$ 10,200
FHLB Advance Due September 2026
Debt Instrument [Line Items]
FHLB advances	590,000
Amount
FHLB advances	590,000
FHLB Advance Due March 2028
Debt Instrument [Line Items]
FHLB advances	950,000
Amount
FHLB advances	$ 950,000